can someone explain why these development/SBC/foss friendly boards always have terrible support?!?? Particularly in these areas: 1. no vanilla kernel support

can someone explain why these development/SBC/foss friendly boards always have terrible support?!?? Particularly in these areas: 1. no vanilla kernel support 2. often require patches and blobs in the kernel 3. worst or nonexisting gpu acceleration 4. just not opensource in general, from blobs to drivers, to closed source boot code why are these boards being sold as developer friendly when they are often less useful than their x86 counterparts, and very often less opensource?!