I've got a cuben MLD Patrol, no signs of wear after approx 18 months and probably approaching 100 nights of use. Cuben is really well suited to shelters, it's very strong and there isn't any abrasion wear to worry about. IMO, durability shouldn't be a factor when using it for a shelter, as long as it's been properly constructed and reinforced where it's been shown (eg MLD).
I would definitely expect to be using it in 5 years.
I also have a cuben-bottomed MLD Soul bivy, and I was a bit more unsure about how it would last: but it's still going strong after having used it every night with the Patrol. I generally have a foam pad under at least the torso (outside the bivy), and I don't sleep on rocks though.
Cuben stuff sacks, no signs of wear, no reason to think these won't last for years.
I haven't used a cuben pack, but packs get a lot of wear compared to a tarp etc. My MLD Zip is a mixture of silnylon + dyneema + mesh, and I've beaten it almost to death in under 2 years of intermittent use, so a cuben pack would have died even quicker. But even a full dyneema pack wouldn't last 5 years of constant bushwhacking.
So, short answer, tarps, stuff sacks and maybe even bivys made from cuben: yes they hold up very well. Packs much less so, too much abrasion.
*edit: to be fair, I did a lot of off-trail with the Zip, which was pretty tough on it*