Buying used vs new speakers from a technology perspective

There is no single, simple answer to these questions.  Some new drivers and technologies are quite good, though not necessarily better than all that preceded it,, and a lot of older gear/technology has stood the test of time.  My all time favorite midrange driver is a horn compression driver made around 1939.  I can also think of a number of older woofers that are pretty hard to beat in certain respects.  There are some vintage parts for crossovers that are still sought after for making modern speakers.  

The only thing I’d be worried about is the foam surrouds on the drivers....they will rot out after 20 years. Other than that, speakers have not changed all that much really. Old Tannoy, Altec Lansing, and Electro Voice Interface were some of the best speakers ever made and are still desirable even today.

Magico, Tidal, Von Schweikert, and Rockport (etc.) all utilize advanced enclosure technology. Tidal and Magico especially use very advanced speaker cone technology. Crossover components are also improved vs 20 years ago.

How they sound in comparison? I am a relative noob and don't have the experience many on this forum have, but the technology aspect is one of my draws to this hobby. 

You will definitely pay a premium for the most advanced technology, doesn't necessary mean you will like it better though.

I love the audio folks who buy lots of new speakers, and regularly. I'd have to have millions to be in that league, but buying their used stuff is great.

Yes, the original Raidho D2 by Michael Borresen is not his latest creation, and by reports they are better, but how much?  For a third of the burl list, I got a lovely used pair in 2016. I'm keeping them; I never thought I could own such a speaker.

Yes there are probably some minor new features on Borresen designs (and well publicized by Lars, of course).  Are they worth $30k add'l to have a new Borresen B02s instead of older Raidho D2s? No, probably not for me.

No. I feel that good speakers are like wine! Vintage is good. I have Tannoy Churchill’s which get better with age….timeless.