People are worse at mental arithmetic than they were in the recent past, so it's not clear that they aren't "dumber" in the sense people meant at the time.

Students score lower on standardized tests in the 2020s than those in the 1990s. So your stance feels misguided. Although I don’t think Google and Calculators are the main culprits, I do think it’s due to larger technology/internet landscape.

I once worked for a guy who typed 7 + 4 into a calculator, after freezing for 1.5 secs trying to work it out in his head. It was in a "stressful" situation (not something extreme, we just were in a hurry), and I'm sure the guy could add those numbers in his head, generally... he owns his own business, after all. It took so much out of me to not move a face muscle.

Sounds like you haven't used it much. It starts small with you forgetting the arcane params to commonly used tools that you don't need to type anymore. Where it will stop nobody knows.

it clearly did make "people" dumber because now "people" believe in AI ;)