> The 80287 (AKA 287) and 80387 (AKA 387) floating point microprocessors started to pick up some competition from Weitek 1167 and 4167 chips and Inmos Transputer chips, so Intel integrated the FPU into the CPU with the 80486 processor (I question whether this was a monopoly move on Intel's part).

I don't think it was, transistor density became sufficient to integrate such a hefty chunk of circuitry on-die. Remember that earlier CPUs had even things like MMUs as separate chips, like Motorola 68851.