@pdreher I agree for the most part and myself I own and love Epi 100 speakers and their little brothers Epi 50, with some updated parts from Human Speakers.
So, as I don’t know the Altecs in question, I don’t necessarily assume that new speakers are "better" than those... though I’ll note that even you have refurbished Altecs.
However, that said, speakers, like amps, have come a long way in "bang for the buck" since the 70’s, especially when you factor inflation, and there are some relatively inexpensive, $2000-5000 range, choices that perform at an astounding level that only the very, very best from "back in the day" could aspire to. Think about the updates over time to the JBL 100, the KLH 5, and the Klipsch Heritage... There are also far more choices in even less expensive "budget" speakers these days that only a select few from the 70s could come close and that only if updated.