Materials and power handling have changed. Lots of materials used today that have taken the place of others. Kevlar, Titanium, Banana pulp paper? No more rotting foam surrounds. Beryllium and polyester. Todays speakers have less distortion and can handle a LOT more power. The good models still sound great and the shit still sounds bad. Todays good pro drivers cost a weeks pay. How much did an Altec or JBL cost in 1940?