That's what I did with the original Stack Untouchables that was on ABC-- once it started getting good, I semi-binged it (not sitting for hours and watching, but seeing several episodes spread throughout a day). Eventually I completed it, and it's one of those that are staples for me.
A very likely possibility-- B/Ws don't go very well with many of today's youth and adults (whether shows or movies), so that's very likely why the movies you love disappeared in the blink of an eye.
I would agree-- if it's something that matters to you, and it's on physical, I think you should have it to enjoy (I take it you did indeed get The Monkees on physical).
I didn't grow up in the 70s (me born in 1981), but I have Emergency! on DVD as well (the all-in-one of that 70s NBC medical/action series), and have enjoyed (and will continue to enjoy) it because it was a class act of flying colors all the way around-- well-acted, well-written, well-shot...