It's only anomalous in that it's the one that happened to survive. As the industry matured, players consolidated, and there were more benefits to one dominant a

It's only anomalous in that it's the one that happened to survive. As the industry matured, players consolidated, and there were more benefits to one dominant architecture with a few implementations than multiple architectures. At some point, CPUs got so complex the instruction set became more of an API than anything actually rooted in hardware, extending the lifespan of the instruction set even longer.