Strongly disagree. Although x86 was dominant on desktop PCs with MS DOS, Nintendo Entertainment System used MOS 6502 which is a lighter version of m68000, while Sega Mega Drive used a full blown m68000. Apple II desktop also used MOS 6502, HP used PA-RISC for their HP-UX servers, and Sun replaced their 68000s with SPARC in late 80-s. Alpha achitecture was so successfull there was a Windows NT port for this achitecture. So it wasn't really game over as of 80s, and even in 90s the market was still diverse. It's only by 00s x86 together with Windows NT series achieved total dominance, even in small server segment.
>So I guess the point is that technology adoption proceeds by evolution, and trying to plan 10 or 20 years ahead of time never works
Right conclusion - wrong reasoning. Quality of product is never a main driver of sales. That's why to succeed you need to market it first and then elaborate some way to make it usable. That's where, for example, Motorolla, Alpha, MIPS failed, and that's where ARM won as an umbrella brand for actually 4 incompatible architectures (original ARM, AArch32, AArch64, and Thumb a.k.a. SuperH).