You can argue that recording technology / quality has improved, but has guitar tone improved since the 70's? Since the 80's? 90's? 00's? A lot of effort has been put into tone chasing. There have probably been more new pedals released this year than existed even 20 years ago. I guess we're still playing vintage guitars and amps, but there have been innovations in guitar and especially amp design. I guess some different pickup designs have been adopted, there have been some innovations in string making... But taking a step back and asking a simple question -- Do we sound better? Do you go to a show today and is the guitarists tone better than if you went to a show decades ago?