Buy a pair of ten year old $40,000 speakers for $4,000 or new ones at that price point?

As long as the drivers are in good shape , rebuild the Xover 
with much higher grade parts ,for 90% of speakers are always 
built with cost savings.athe Xover is the heart of the speaker 
weak link in the chain , Ihave 20 years of  modding , this includes electronics also , the payoff is Huge often minimum 10-20% sonic  
improvement  lthese. Are facts quality does count .
i  just rebuilt my whole crossover ,and rewired my whole system 
with the best VH audio Thin film Teflon Solid Core 0-CrystalCopper
which made substantial increase in. Resolution and system synergy and saved $1,000s in what a new lesser speaker,electronics could provide. All electronics,speakers  invest 
less then 25% of its cost including the case work ,or cabinet actually goes into the cost ,the rest overhead ,and markup ,hat is why Modwright has been so successful in the past putting in premium parts in stock equipment.

I posted an answer in the amp section not realizing the op was fishing. 

DACs change too much and we need the newer technology.  I guess I am wondering in what ways DACs have changed that much over the years?

It is hard to answer a question where we do not have an idea of the product.  The 10Ts are a good speaker for the $2K especially.  There are many older speakers that have great sound.  IMF, Alon, KEF, B&W 801, etc.

Happy Listening.

"All electronics,speakers invest less then 25% of its cost including the case work ,or cabinet actually goes into the cost ,the rest overhead ,and markup..."- audioman51


I do know that there’s one place that’s not the case, it is however very rare.
I know a bespoke builder in Australia who uses 12AWG hand wound air core inductors, Duelund cast capacitors, Duelund or Path Audio resistors, ultra thin, high purity copper ribbon internal speaker wiring, no PCB whatsoever. Makes 4-6mm steel lined enclosures, the design tuned by ear and a stethascope over years.
And after the speaker is fully assembled, had a tuning bay on the back to fine tune the circuit which is measured and listened to, the drivers had already been broken in, before installation. By a craftsman who used to sight sniper rifles. Almost nobody knows him in USA, well except some people who are very lucky and some recording studious.

Yeah, he’s not a wealthy man.

Buy the used ones if they can be listened to and impress you. I build and repair speakers and see the effects of time often. 10 years isn’t even half the life expectancy of quality drivers and crossovers. So if undamaged and play well you -have a bargain. Driver technologies and crossovers have not improved that much. Not at the $4k level today compared to $40k a decade ago. The older design has the possibility of being much better. I said “possbility” because there is no guarantee the older speakers were any good new.  Enclosure design has improved, but speakers incorporating that advanced technology cost more than your hypothetical $4k today. If the older speakers wow you, don’t let age be a concern.