Blockbuster didn't only stock Paramount pictures -- and people wouldn't have had much patience for rental groups that worked that way when there were alternatives that didn't -- piracy being the alternative here.
Keep in mind the this was only because of some monopoly busting decades earlier: https://en.wikipedia.org/wiki/United_States_v._Paramount_Pic....
With Disney owning so much of the production and now entering the distribution/retail side there might be some more anti-trust cases coming.
Netflix can only stream what they are allowed to. If you want the convenience of the Blockbuster model there are always rentals from Amazon, Apple, Google Play etc. Yes I realize that some movies aren’t available for rent.
they used to (and still do AFAIK) have a pretty good selection of DVDs to have mailed though. I think people hoped that eventually the streaming offerings would come to be as broad as the mail-order selection, which doesn't seem unreasonable from the perspective of 2009 but obviously isn't happening today. there's also the fact that music streaming services have mostly succeeded at offering a very wide selection of music to their customers (even free accounts!).
frankly I don't know enough about the music, tv, and movie industries to tell you why it turned out this way, but to the layman it does seem like a perplexing "shut up and take my money" situation. if a service launched with a really good catalog that could at least match the convenience and quality of torrents, I would be willing to pay quite a hefty monthly fee. I have very little interest in paying for five different streaming services that will still inevitably exclude a couple of my favorite shows and movies.