Vintage vs New

Vintage has inherent issues with things wearing out. Electrolytic Filter caps for example do not last forever and need to be replaced. Contacts, relays, potentiometers, Lpads all oxidize over time and can cause problems. Some woofer surrounds deteriorate and have to be replaced. Unless you are willing to address ALL such issues rather that employing  a piecemeal approach, vintage is not going to work out in the long run in my opinion.

I thought that with millercarbon shilling for Tekton that we finally caught a break from his constant promoting of Synergistic Research.  I guess I was wrong...

" Maybe someone so sure there was great wire back then can name me the 1970's era power cord they would put up against a circa 1990's Synergistic Research Master Coupler? This should be good..."

Vintage will likely require some crossover parts replacement, but I'd say lots of current loudspeakers would benefit from same. One of greatest bang for buck upgrades is replacing common run of mill capacitors, resistors, inductors in crossovers.

There have been great strides in modern production film capacitors, resistors, inductors. Check out brands like Jupiter, Duelund, Jantzen, Audyn, Miflex, Mundorf. Could go on and on. You can 'tune' speakers to individual preference with judicious choice of components. My present Klipschorns most definitely don't sound like any stock Klipschorn. The necessity of replacing certain crossover parts, and perhaps speaker surrounds as mentioned above, are an advantage of purchasing vintage, IMO. You've already opened up speaker, perfect chance to upgrade, no warranty issues.

Not willing to open up and mod or replace, stick to modern.

The comment that 70s speakers were voiced for the music that was most popular at the time was spot-on. That music was rock (the Rolling Stones, Led Zeppelin, The Who, Grand Funk RR, etc). The speakers were built with full-range capability being the most important factor (no subs back then), while accuracy was mostly an afterthought. JBL was considered the best for rock, while brands like Advent, AR, and KLH went for a more balanced presentation. Mated with good electronics from that era that have been kept in good shape, those combos still provide a sound that has a lot of meat on its bones IMO. My little Pioneer SA-7100 is a delight, driving either a pair of large Advents or a pair of ADS L-810s from the 80s, and I don't feel the need for a subwoofer. A Musical Fidelity A-308 and B&W CDM 9NTs satisfy my cravings for a more refined sound when I'm in that kind of mood. In my book, it's all good and we should just enjoy the ride.