Without Compaq reverse engineering the BIOS and doing it in such a way that IBM could not release their lawyers on them, there would not be an open PC, regardless where those parts came from.
We would all be using variants of Atari, Amiga, Mac, Archimedes by now instead.
Which ironically is what laptops, 2-1 and mobile platforms have become.
There would be no open PC clones if IBM had succeed suing the clone makers or if PS/2 MCA architecture had actually worked out.