I make it a rule, anything I think I'll eventually need to refer back to, I download it as a hard copy. Same for videos. My Viddly service (successor to Free YouTube Downloader) is having issues, and I need to fix that. Sometimes, with freeware, you get what you (don't) pay for, and in the interests of being frugal, I always use freeware unless I have no other choice but to buy or subscribe to it.
Things can and do disappear. As I noted in another post recently, the scene on YouTube from the 1987 miniseries Amerika, showing the bloody siege and burning of the United States Capitol by "fαℓѕє fℓαg" communist agitators masquerading as counter-revolutionaries, the goal being to destroy the federal government (or what was left of it), has been taken down in the wake of the events of 6 January. Gotta wonder why.
Don't be surprised if the entire miniseries eventually goes down the memory hole. If you were ever going to spend 14 hours of your life on any secular pursuit, please, please watch Amerika. You'll see. My wife, who grew up under communism in Poland, watched the entire 14 hours with me, and she said that it was really pretty accurate. She'd know if anyone would.