Jim Blinn was working at Microsoft and is now retired somewhere in the Seattle area. He's pretty easy to contact from his website if you want a few more moments on memory lane. Thanks for checking out my book.
@LiketoBike makes a good point about having tghe ability to get back up to speed on subjects learned long ago.
There's another aspect of having been a practicing engineer decades ago - the old stuff becomes new as new engineers re-discover what we once took for granted. Sometimes the old skills are exactly what is needed to solve today's oroblems.
I fall on the other side of the do-I-need-this-math debate. I'm an RF/microwave guy, with an electromagnetics background. I work at a small firm where we do lots of things. We do a mix of signal processing, RF, antenna, electro-optics, modeling and simulation, mechatronics, embedded, and a host of other things. I still work with Maxwell's equations (you CAN do useful quick-and-dirty things with them, believe it or not!). Others are doing matrix-heavy DSP that requires derivations. We use Matlab a lot. (Tools like that mean that I can use a function - after reading its documentation and making sure I'm using it where it is valid, with the expected level of accuracy, with arguments in the right range, etc - rather than having to code the function up myself.)
So don't count on NOT having to use higher math. Working at my employer requires it. :-)
I remember my first interview. I mentioned somthing about a pot core transformer which we had considered for our design project, but the truth was, I knew little about the component other than its name. Yep, I was name-dropping, trying to score some interview points. :) I didn't realize that the person interviewing was in charge of transformer design for the company (which built T&M equipment). "So tell me more about this transformer," he said. Suddenly I was wishing I had not brought up the subject. Gulp.
That said there are some subjects I wish I had studied harder, such as transmission lines. Perhaps someday I'll reread that text book. I should also dig out my Halliday and Resnick physics text and reread the electromagentism chapters. The recent news on the synthesis of a magnetic monopole has got me interested in physics:
Thanks for reading! I'm sure some engineers need to use it, but I think it's pretty rare. As "liketobike" alluded to, understanding how to go back and relearn things is possibly the important part. That and the process of learning it is probably important.