IBM did wish to maintain control, that's why they copyrighted the BIOS. But when Compaq reversed engineer it, it was obvious that there was no way to sue without inviting more legal scrutiny.
My other point is that some Apple app store apps can use APIs that every other app would get banned for. People complained about that when it came MS; It's not better when Apple does it.
That also isn’t true. Compaq had to do a clean room implementation so it wouldn’t get sued. The anti-trust suit was dropped in 1983 - around the same time that Compaq reverse engineered the BIOS.
My other point is that some Apple app store apps can use APIs that every other app would get banned for. People complained about that when it came MS; It's not better when Apple does it.