People have been talking about competing and trying to compete with the nvidia GPU/Cuda stack for almost 20 years (since the start). There have been various efforts. They have all fallen flat. Nvidia isn't standing still, the target keeps moving forward.
To suggest Nvidia will have the game to themselves for another 10 years might turn out to be wrong, but it isn't naive. You are the naive one here.
There hasn't really been any significant money in competing with cuda however. Nvidia had a bit of a gaming premium over amd, and crypto really boosted all GPUs...but until about 3 years ago, there wasn't literally trillions of dollars on the line to replace cuda. There is now. Companies ARE replicating it. The Mi300 is very competitive on token throughput as far as I'm aware.
No one is sitting around. I'd argue if there was more wafer supply you'd see amd/others undercutting nvidia...but it's hard to when supply is incredibly constrained.
They are trying. They are not succeeding yet. Maybe in 10 years the gap will be closed. Maybe it will not. I'll guess the latter. Nvidia's situation has changed too - the R&D $$ they have to spend to defend are dramatically higher. Nothing stands still, it's harder to catch up than it seems.
To suggest Nvidia will have the game to themselves for another 10 years might turn out to be wrong, but it isn't naive. You are the naive one here.