Without going into a super deep and technical discussion, just because RISC-V is an open ISA does not mean DeepComputing and/or other vendors will implement a fully open stack. For example, Framework will be releasing another update of the Framework Laptop 13 with an alternative RISC-V mainboard:
Even if RISC-V achieves feature and/or performance parity with x86, vendors could still simply implement proprietary firmware and hardware into the silicon itself. Furthermore, even if the entire stack is completely open, that does not mean it will remain open for every future revision, which is exactly the siloed trap Raptor Computing Systems is still caught in from POWER9 to Power10, along with the rest of the FSF movement.