These are all enforced via specialised companies and it's about actively defending copyrights rather than finding more income or stopping videos that might theoretically otherwise have to pay a licensing fee (but of course never will). The fact that a lot of the most absurd copyright holders tend be old men I think is mostly because they are all old enough to have been around for the the MP3 / Napster years and have they have regressed into responding to people listening to their music in "they took our stuff!" South Park style.
Because the problem here is that the world has changed and lots of copyright driven industries haven't. In practical terms, copyright mostly exists for bad actors to extract value for things to which they add marginal value. So for example, the record label was traditionally talent search, agents and physical distribution which in any sensible world would earn them minimal, flat fees. Most of their business is euphemistically called "trucks and sheds" by management consultancies precisely to indicate it's mundane, marginal value and that it should be in service of the copyright holder rather than using copyright to artificially restrict artist and consumer rights so you turn driving a truck of CDs up the M1 into a way to print money.
In all of this it's important to remember that the music industry should be no different from ever other industry that has seen the old ways of working disappear and by now most of these companies should have found something relevant for their artists and consumers and socially useful to do or else ****ed off. In my industry (finance) and my profession (software engineering) everything has changed and it should be no different just because the this you make is a song instead of a computer program, or trading platform.
I do think this is a music specific thing though and it's very noticeable that since I got back into guitars, music software comes with these weird licensing utilities that require you to install come cancer like software -- for which you cannot see the source code and could literally to do anything -- and enter a code. This sort of thing died out about 20 years ago in the rest of the industry as a) everyone is connected to the internet now and b) for sensible people making your customers jump through hoops to prove they are not criminals is considered perverse.
Of course copyright has to exist and if I try to release a cover of Beyonce's latest or play endless Top 40 hits for the customers of my bar then I should be stopped. But stuff like copyright hassling of Rick Beato should be covered under a broad fair use exemptions and their should be some reasonable burden on the copyright holder to prevent frivolous takedowns. I refuse to believe anyone really things Don Henley would suffer if the limit to how much Hotel California you could use in a music theory video went from the current 4 secs to, say, 20 secs.
In other words the free software people (and Vuk!) were basically right about copyright. In its current form it's ultimately a bad thing for the general good.
Matthew
PS Days of Jarrett sounds like a CIA torture programme