Why would someone spend a bucket load of time and money on r&d for such a small, if any, return? Doesn't make much business sense...
you talk about old amiga here, there are actually nearly no money in it, but there is a demand and of interest for some to make the old amiga a bit better. and there you find your answer why people like jens make these things he makes, it may not make you rich but the challange and thinkering is also the fun part of it.