If you look at the natural experiment on that in society right now, much worse.

Many people today do math only with a calculator and correspondingly lack any sort of numerical reasoning skills whatsoever, despite having learned both mental math and numerical reasoning in school. That growth of innumeracy coincides with the rise of calculators and computers who do it for you.

Also, students are taught in more advanced classes to use calculators (and later computer algebra systems) as a tool. This comes after they have learned the basics, not as a replacement for the basics.

Writing (hello ChatGPT) and math are like muscles: use it or lose it. If you can't do the basic versions, you can't do the harder stuff either.