The PS2 was released in 1987, 5 years after the US antitrust suit against IBM ended, and after IBM no longer had a monopoly position in the PC market.
It was a different era and the horses had left the barn. The PS/2 was a dead end. The original PC architecture, openly evolved, is still generating hundreds of billions in revenue each year - just not for IBM.
How does that fit in with the IBM PS/2 design, which was carefully closed?