I guess old unix persons do use bc. But even older unix persons, like you and me, use dc. Oh, and I still have my trusty old HP48GX calculator that I bought nearly thirty years ago. Algebraic notation is fine for paper, bur RPN is best for calculating. I am glad I can even have an RPN calculator (PCalc) on my phone now.
rpn for for the win I guess ;-). I actually didn't get to try my first linux stuff until grad school in the 80s. I wish I had saved off all my init files from then to see what they look like now.
Back in the day (Unix Seventh Edition) bc was just a front end that compiled the expression and piped it to dc. My take it is most people didn't find rpn a win, and bc was the fix.
I used bc's compiled output ("bc -c") to learn how to make dc jump through hoops.
It also gives the math result here of course.