Look guys, they didn't spend all that time developing OS4 just to let it rot. They've effectively thrown down the gauntlet, "if you build it, OS4 will come."
AmigaOS is, and will always be, very tightly controlled hardware-wise. They can cover specific hardware, but when it comes to expansion that will have to be done by US, the community.
So relax and enjoy. The moment we've all been waiting FOREVER for is nearly upon us.