Iterative development for two player strategy

To answer your question, I don't know of anything like this and have considered building it myself. I find it challenging to find enough playtesters to give my attempt at a board game the kind of rigorous testing I want.

One thing to keep in mind is this: as more video games went to mass beta tests, the beta tests themselves shifted in how they were conducted.

Not to bore you, but this is important for understand player expectations and how they have shifted: Originally the software development of going from "alpha" to "beta" meant all the primary features had been settled on, now began the process of refining them. When video game makers first started having massive beta releases, players didn't know what they were getting into and a lot of games burned and died because players thought they were too buggy and unpolished. But that is exactly what beta used to mean.

These days beta releases are more about promotion and testing server/network capacity. They are practically finished games, and the graphics/gameplay will only be moderately updated, in much the same way updates continue to happen after release. For many video game companies, the "alpha" testing has been extended to cover what previously was tested during the "beta".

If you're considering doing this for a board game, you have to make sure you distinguish between testing a buggy unpolished game versus mass marketing a polished game that only needs a few tweaks.

Personally, I want to create the former. I want to create a space that uses TTS and where board game designers can playtest each other designs and help give feedback from the point of view of TESTING rather than PLAYING. It is a totally different mindset. I want people capable of telling me why and where my game needs work, rather than just telling me it is buggy and unpolished.

Yep. I imagine Asmodee or Stonemaier Games would have some measure of success if they pioneered this model. Asmodee does something similar with a number of their tabletop-to-mobile/PC conversions already, and Stonemaier has a strong online presence due to Jamie Stegmaier's KS depth (among other things).

You bring up an interesting point though, and this reminds me of the Steam "early access" environment. Someone posts a first game, advertises it as early access, and starts on the long treadmill of updating until the game is "finished." Along the way, players constantly ply the developer with questions and offer suggestions for feedback and additional game features.

Generally speaking, unless a designer runs a tight ship this kind of model becomes highly-susceptible to feature creep and bloat, as the temptation to gain and retain followers is high. In a worst-case scenario, some disgruntled YouTube reviewer would sink their fangs into it, and doom a game in the middle of development.

...Maybe that's why we've not seen too many (or any?) physical tabletop games developed this way yet. By contrast, indie video games can be developed by a single individual in a lot of cases, and the physical/inventory costs are nearly nonexistent in comparison.

If this would work at all, it would work better with an online version on something such as Tabeltopia or Tabletop Simulator.

My wife and I love testing games. There are two other designers among our play group. (Though none of us have made it past play test yet.) The host of our group has seven book cases of different games, several of which were just published when they bought them at game conventions. And I just met another designer who doesn't live too far. He and I are discussing swapping games for each others play group.

If anyone wants to send us rules and list of game bits, I will pose it to the group and try to get it played. They're very willing to tell me where mine are lacking. I have a small but respectable number of game bits to utilize (to try to prevent from costing designers too much on recreating/sending a proto-type. It may also give me an excuse to acquire more or use my 3d printer more.) To give you a sense of the feedback, here's a summary of some of the things I tested and changed or am considering changing based on feedback:
-My kids game was adorable but first draft had players waiting too long while the active player determined their move. Switching from dice to cards gave players time to deliberate their next move while others were taking their turn. Second draft still ran too long to hold the target audiences attention, so I'm shrinking the board a bit and reducing the number of points needed for victory for a third draft.
-My movie card game allows someone to just screw over everyone at too many points in the game. I plan to reduce the number of screw the group cards slightly. A few people mentioned some of the random initial set-up may put someone at a rather large disadvantage (which is discouraging for first time players and turns them off the game). I'm debating on adding a casting set of cards to allow changes to some initial setup. Additionally this will allow for a sixth player.
-My monster fighting card game has received the most intrigue thus far. But I really need to have small rewards and/or scoring for defeating each monster, rather than a straight survival game. I had a sense of this in development and had the foresight to keep a slot on the cards open for it, but this first draft was mainly to try balancing it. Not quite finished with the balancing, as no one has won yet, but the last few tests were close. I've received requests to try this one again.

We've actually done some testing for someone on here before. The creator of "Compliment Punch" was gracious enough to send a deck over and we tried it out. It was an interesting social experiment, but ultimately flopped in our circles for a variety of reasons, which we were happy to share with the creator.

Honestly, after getting a game or two on the shelves, I want to start a Podcast for game designers to open up about their process, from concept, to design, to prototyping, to play testing, to redesign, to blind play testing or killing it, to publishing, to getting it on shelves. Talk to publishers about what they look for, discuss strategies of self-publishing with successful kick-starters, when and where to get game bits, if and when to get your own art, etc, etc. Most notably, I would love to interview people who are about to, or just have published a game to help promote them.

I'm getting long winded and digressing a bit. All this to say, if you think you're ready for a blind play test, feel free to send it our way. (Please be aware, we will not return anything sent though.) We'll run through it with our group and let you know the results.

Lastly, I've been in touch with IUPUI's game development professor. He is super busy, but they have two student groups who do nothing but play test board and video games. It sounds like one is very rigorous and blunt about how they like/dislike the game. The other group is apparently more casual and will only give a sense of elements they liked. But I've had difficulty keeping in touch with this guy to get the ball rollin', as he is not very responsive. Though it does sound like other universities are having these groups pop up too. (A couple in my game group teaches at Miami University and are starting to try something similar.) So there might be another resource for developers to try?