After I got banned from Facebook in 2011 (for using a “fake name”, which is actually my real name) I took a similar line of thinking: I can’t trust Facebook (or Twitter, or Instagram, or whoever else) to be responsible custodians of my content, so I shan’t. Now, virtually all content I create is hosted on my WordPress-powered blog, at my own domain, first and foremost… and syndicated copies may appear on various social media.
In a very few instances I go the other way around, producing content in silos and then copying it back to my blog: e.g. my geocaching/geohashing expeditions are posted first to their respective sites (because it’s easiest and most-practical to do that using their apps, especially “in the field”), but then they get imported into my blog using a custom plugin. If any of these sites closes, deletes my data, adds paid tiers I’m not happy with, or just bans me from my own account… I’m still set.
Backing up all your social content is a good strategy. Owning it all to begin with is an even better one, IMHO. See also: Indieweb.