My father gifted me 35 year old speakers he had stored in his attic.

I installed them on an old Marantz amp, which is also connected to my (new) TV. As he visited me, he couldn't believe the incredible sound coming from his own speakers. My friends are shocked by it too, thinking I'm some audio buff that invested 20K.

My dad regretted the gift, went to buy the same amp yet with new speakers. Various sets of it, and failed to come close to the ancient set.

I'm not sure what exactly was innovated in 35 years of audio, but my guess would be costs, not quality.