had the same thoughts this year as my SBLs are nearly 30 years old (but still sounding great). My solution was to buy some really late mk2 at a good price and treat them to a new paxo from Naim and new grills from Tomtom. Under 600 all in for a true classic. Naim still supply tweeters too should I need them.
There is nothing out there new that delivers in quite the same way. I was cutting edge back in the day, happy to now be anachronistic...