Please allow me to introduce you to the wonders of M-Disc Media:
https://en.wikipedia.org/wiki/M-DISC
Developed by our friends at Brigham Young University(say what you will about the Mormons but they lead the world in archival media storage), a single M-disc is supposed to last as long as 1,000 years. Even if in practice its only 1/10th of that, that's still longer than you'll ever need to store stuff for.
You do need a specialized M-disc compatible blue-ray burner, but they don't cost any more than a regular burner. The media is significantly more expensive, but the shelf-life makes up for it in the long run. I have about a terabyte of must-have media archived to m-discs so far and over the rest of my lifetime I expect it to cost a lot less than buying new hard drives every 4-5 years.