I've been buying film for long-term storage since digital SLRs started becoming affordable and Kodak and Fuji started discontinuing film. At the time, I was a high school student. I decided back then that if I still wanted to be able to shoot certain types I had been using that were likely to be discontinued, or if I wanted to try types that were already discontinued (like Panatomic-X, for instance) I would have to freeze it. It helped that at the time there were a good number of pro and serious amateur photographers selling their unused, frozen film. I knew prices were going up continuously. I also decided back then that buying even some of the types that were still produced, made sense, because I was on a tight budget, and who knew when my favorite types would be discontinued. It would come down to being able to still shoot, or not. I'm still on a tight budget, so I'm glad I don't have to pay $16-20 per roll now all the time. I'd only be able to shoot and process 5-10 rolls a year at those prices. I still buy maybe 20-30 rolls a year now, but those are mostly less expensive types like consumer color neg, or stuff that won't keep, like high-speed film (e.g. a roll or two or Portra 800 every so often). I'm actually getting into ECN-II as well, now that there are finally some good self-processing options available. Been hoping for that for over 20 years. Not sure if I'll try E6 myself anytime soon...might keep sending it out. Also, as far as C-41 goes, I'm fortunate to have a good local lab that does it.
Additionally, when Kodachrome was in its final few years, I purchased enough to take me through to the end (Remember member PKM_25? He was shooting a huge multi-year project with it at the time. I almost got to meet him...actually talked with him on the phone once. (It was interesting to learn much later that a movie had been made about someone rushing to process the final rolls.) I got a small group at my University together to shoot Kodachrome before the deadline. It was great to see a number of people try it for the first time.) I even have a few rolls of film from the late PE in freeze.
Up until recently, I stored my film in my grandparents' freezer. They are gone now, unfortunately, so I need to find another freezer. I'm certainly not going to let it all sit out at room temperature and degrade. And I'm not going to sell it, give it away, or try shoot it all in a short time...I know it might sound selfish, but it's my film...I paid for it, stored it, and I bought it to take me through a long time period. I have more emulsion options than I would have if I hadn't started buying back then, and I can shoot and process a slightly larger quantity per year than I would be able to otherwise. It's all about the look.
That said, according to notes, I likely have at least 6 rolls, possibly more, of frozen Fujichrome Velvia 100 that I purchased in the last couple of years, and apparently will need to find soon, and shoot within the next month or so and then process. Never thought something like that would happen with such a quick deadline, but I'll figure it out and do what I have to, like others.