You guys are bumming me out with this negative talk!
The idea of doing audio DSP on cheap commodity hardware is not going anywhere. In fact it's only going to become more pervasive as the available hardware becomes cheaper and more powerful. Axoloti is a first step in what I see as a long line of future devices.
I think part of the problem of achieving Arduino or Pi - level market penetration and engineer interest is that there's already a huge ecosystem of plugins/apps/devices for music making. Arudino or Pi etc fill a niche that doesn't have a direct alternative on hardware people already have. There's also a huge ecosystem of more "engineering" level DSP dev boards and toolchains, etc. I don't think the musicians aren't going to go out of there way to hack around with hardware necessarily unless it's really straightforward or offers something different; they already have laptops full of plugins and apps. The pure engineers are going to gravitate toward stuff that isn't so focused on sound synthesis and processing; they might be doing DSP in some completely unrelated domain. Axoloti is in a bit of a gray area in between these two use cases. I think that makes it tough to turn it into more of a universal standard.
So part of the issue is usability. A musician needs to feel reasonably at home and not overwhelmed with technical detail. Another issue is communication. It needs to be clear what a board like this offers that is different from what people have already. The simplest thing I can think of is that it can be standalone. You can make a proper instrument that can be played away from a laptop.
TLDR: I'm an engineer. I'm interested. I'm going to do everything I can to make sure that the spirit of this project lives on.
BTW I'm sick of forum discussion all of the sudden. I think it would be interesting to try to get people together on IRC or Discord etc to discuss this stuff more actively. Ping me if that sounds interesting to you.