Capacitor Size

I'm curious to know about current capacitors vs. vintage caps...

Are current capacitors physically smaller than equivalent capacitors from back in the day?

The reason I ask is b/c I had an old amp recapped and the new caps are quite a bit smaller than the old ones. The tech said that new caps are physically smaller than old style caps of the same capacitance... He also went on to say that the ones he used in my amp are of even higher capacitance than the old ones... (even though they are only about 2/3 the size of the old ones).

Have I been snowed, or are new caps actually smaller than old, equivalent versions? (i can't physically see the caps' specs because of the way they are mounted).

Any insight would be appreciated. Thanks!