To clarify, most of the fan-recorded Doctor Who episodes recovered were of the audio only. Home video recording was extremely expensive until roughly the 1980s -- I am not aware of video recovered by home fan enthusiasts. Most of the recovered video episodes have been 16mm telerecordings intended for overseas broadcasting.

Doctor Who is lucky in that there was a nice size fanbase from the get-go. Some not so popular programs from that era are indeed gone forever. (An example I can think of offhand is the 1960s soap opera United! https://en.wikipedia.org/wiki/United! -- reportedly all 147 episodes of that program were wiped.)

As far as this act goes, my initial impression is that standardizing a mechanism for mechanical royalties is probably a good thing overall, same with the added protection for those on the production side. But the CLASSICS act portion strikes me as very rent-seeking in nature, I'm not a fan of infinite copyright economically.

There were a handful of episodes where the color was recovered from NTSC U-Matic off-air recordings, with the luma coming from the existing black and white film.