It's pretty hard to say they last when foldables have been around less than a couple years.
If I don't drop it, I expect to be using my Pixel 4 for years yet. I used a Nexus 5 until a few months ago, and it was probably a decade old by the time I retired it.
That's not to say they won't last as long, I'd love to see it since I'd like to have something with a small pocket size and the screen naturally protected. But it's a bit premature to say they "last".
Don't have the Fold but the Flip 3. I'd say it is pretty much as resistant as any other phone I had. If not more so because the main screen in protected when folded