Everything is better than something else. WHICH is better, and HOW it's better, is tricky.
WHICH: Yes, most modern zooms are better than most older zooms. Yes, most older primes are at least as good as (or better than) most modern primes. With many exceptions, of course.
HOW: Modern coatings reduce flare. Modern complex optical designs can reduce aberrations. But older simpler optical designs may seem to have more dimensionality & character & magic.
IMHO: Modern lenses are great for recording images. Older lenses are great for interpreting vision. Simplified: I use modern zooms to TAKE pictures and older primes to MAKE pictures.
What is the best generation of lenses? I'm currently crazed by older German & Russian glass, especially with shiny aluminium bodies and many iris blades, ooh ooh. Those in Exakta mounts are pretty cheap, and easily mounted on PK cams. No modern coatings, so use a lens hood and don't shoot into lights -- unless flare is desired. Many of these guys, and Takumars, are small and light, so it's no big deal to have a few in my bag. Are they the *best* generation, or even *my* generation? I dunno, but they work for me.