Interestingly, there is a thread on RWT that talked about this where Linus Torvalds was involved. It seems that it wasn't until 486DX2 in 1992 that x86 was beginning to beat RISC and even 68040 on the lower end. And remember that 33Mhz 386s did not even arrive until 1989 or so.
This is very true. At that time, even 68K-based workstations ran circles around any x86-based design. x86 was, however, cheap, high-volume and with a lot of compatible hardware, so there was sufficient interest to pour resources into it.