No, I don't think so, I would rather say that altcoins have helped the adoption level of Bitcoin greatly because if there were no altcoins at all, it would take more time for Bitcoin to spread around and it is altcoins that make Bitcoin look better because people compare altcoins with each other and also with Bitcoin, and when they find out which one is the best, which is Bitcoin, of course, they become more interested in Bitcoin after that.

One more significant thing that altcoins have done is that their teams and creators promote their coins and tokens which in return makes people investing in their projects turn back to Bitcoin eventually because once they get in the industry, they start looking here and there and doing their research, and their final destination becomes Bitcoin. So altcoins indirectly have supported the adoption of Bitcoin.