> as already happened with Intel I guess
In which sense? Intel is neither a full monopolist (AMD, ARM) nor has progress stalled (we're still getting a regular cycle of new generation CPUs which improve on the previous).
Intel didn't do much to improve their CPUs while AMD was out of the competition with the Bulldozer disaster.
Intel had something very close to a monopoly for a long time. ARM wasn't taken seriously for desktop or server applications, and AMD was unable to compete with Intel's top-end CPUs until Zen (and with it Ryzen and Epyc) came around.
Intel had a monopoly on bleeding edge cpu for a long time until they got stuck on 14nm for years, allowing TSMC to catch up and providing AMD the means to compete.
In a the best of timelines, intel, tsmc and samsung (and glofo maybe?) Would all have competitive fab nodes.