A moden speaker will not necessarily better an old speaker.
Modern materials and techniques mean that drive units distort less and perform more linearly, speaker matching is much better, and crossovers have to be less complicated.
However in the old days they used to design speakers by listening to them, rather than using a computer without any reference to comparing them to a real source, such as human voice.
This can make a big difference.
At the 2002 HFN London HiFi show the room with the 35 year old LS3/5as, driven by 30 year old amps, was one of the best sounding rooms in the show…