And I think the only reason Microsoft exists is that, when IBM developed their first PC, they purposely sought an outside developer for the PC software because they fully expected anti-trust action if they developed and owned both the hardware and software for their new PC. - IBM could definitely have developed their own PC software if they thought they would have been allowed to do it.
Now these giant tech firms just buy up any new firm that might become competition and not a word from the US government.
IBM had OS2 Warp. It failed. They still use it internally.