I worked in a family business for eight years before I went back to school. By that time every engineering student I knew was pining after the best programmable scientific calculator they could afford. I was no different than the rest. Of course I wanted the best HP, but had to settle for a cheaper Casio graphing calculator. I also had a little radio shack TRS 80 handheld computer that had BASIC built in which was pretty handy.
These were useful devices and in many ways allowed students to go beyond what we would have been able to achieve without them. But these days it seems like things have gone off the rails and many students seem to be losing there ability to reason out even basic problems.
A couple weeks ago I cut down six tall trees in our front yard. The tallest was 120 feet according to my calculations using one of those walk behind measuring devices with a wheel and an adjustable protractor with a level. I wanted to make sure that when I dropped it in the right direction that it would not take out the neighbors’ fence. My best friend was an engineering student also, so I asked him to double check my calculations and measurements. He had forgotten all of these basic trigonometric functions that we both learned when we were about 12. Then the neighbor came out to see what we were up to. He actually spent almost his entire career working as an aeronautic engineer. He had an app on his phone that cost $2 and could be used to figure the height of just about anything using the camera, but he was also having a bit of trouble remembering the basic trigonometry. It was actually quite funny to me.
I used those calculators too, the TRS 80 had some features that other programmable calculators did not have, like testing a solution and one click back to the equation. I thought of that as a great learning tool.
You are also right about what has been lost. As a math teacher, I felt embarrassed taking my calculator out because I was so slow doing math in my head. I knew others who could do very large problems in their head and get answers that were close enough to be the basis for an engineering trade study.
Funny thing about the early math, after teaching it for 9 years, I could recall how to do every problem and often could recall the “trick” that a student needed to get to the right answer quickly. I cannot do the really hard ones, like you see on youtube, but the SAT test questions are not a problem anymore, and I suspect I could figure out the height of a tree. Students can learn the same things we learned, if asked to do the same problems. The solution is in how math is taught, and how much the teacher knows about the math they are teaching.