I don't think it's that much, 50 000€ is 50€ x 1000 amiga users. Frankly going by eBay prices and Classic/ppc amiga (OS4/MOS) users on forums I'd say there would be plenty people willing to give those 50€ as even donation!
You never raise 50000€ from donations. There probably arent even one thousand Amiga users left...
And of course, when that board goes to the production you pay all expenses in advance. Which means you must get funding somewhere, maybe from a bank.
And this is just to get some PPC card for old 15 years old Amigas. It makes no sense. Spend 50k only to run OS4 or MorphOS on old Amigas... most Amiga users dont even use AGA which makes me wonder why they need real Amiga at all in these days... maybe nostalgia and retro feeling but I dont see OS4 or MorphOS in that context. They need new hardware, not some old G2 technology derivate from 1993.
And again you need 68k cpu or it is useless to most users. You cant run old games and demos in OS4 or MorphOS due to memory protection and other changes.