Well, this is kind of embarrassing for me. I never left that 'old school' CDs and DVDs world that you talk of.
I agree. And owning hard copies is a poke in the eye to those who want us all to 'Own nothing and be happy'. Assuming that they are successful, and manage to fully implement their dystopian vision, I can well imagine that removing access to Spotify and similar services would be one of their sticks that they use to beat the non-compliant.
I think cassette tapes were only really useful for playing music in cars, and other situations where vinyl was impractical. Also good for taping the Top 40 on sunday afternoon, so that you could listen later and fast forward the rubbish songs.
As people switched to digital streaming, I noticed that the price of CDs plummeted. And at the moment there's a surprisingly large number of cheap, and often mint condition, CDs available in charity shops. Many of these cost more than £10 when released, and they are now being sold for a few £s.
The strangest thing is that I've seen used cassette tapes selling for what I consider to be a high price on Ebay. Who on earth is buying these? Is it the hipster types? I just don't get it. CDs and vinyl yes, but not cassette tapes.