Tech design and development seems, to me at least, pretty much naturally opposed to the "being kept in check with competition" state - as design isn't really a cost that scales per-unit, the company that sells slightly more can afford to put more into development at the same per-unit margin, which snowballs. At some point, they own the entire market - or enough that they functionally control it, and start leveraging this position. I'd argue we're seeing this from Nvidia right now.

People talk about AMD being competition - but from most stats I've seen, they're ~10% of dGPU sales, with Nvidia being the other 90% (with new Intel offerings being pretty much noise now). That means that if they invest the same proportion into development, NVidia nearly have 10x the resources.

It may be that tech companies like this would "naturally" form a monopoly without outside (IE government) interference, as the only reason that multiplier of development resources doesn't completely crush new entrants is rather extreme mismanagement, or a new segment is created where the design resource don't really cross over that much.

I don't see anything like that happening in the short term, if anything there seems to be more opportunity for cross pollination of development within these corporations, as there's a fair bit of design similarities between various silicon (GPUs, CPUs, accelerators for the current ML techniques etc.) that may encourage more consolidation in the whole semi market to take advantage of that, not less. But again the only thing stepping in the way of that seems to be governments trying to keep national interests, like the blocking of NVidia buying ARM to pull in one of the big CPU players. Plus all their other IP that they may benefit from, like low power GPU designs or other accelerators ARM have designed.