Well, it's gonna depend somewhat on how you treat your gear. If you're rough with it, then neither of those two cameras is gonna last very long. But if you treat your gear properly, you can expect lengthy service lives out of either one. For example: I bought my wife a first model Rebel in 1990. It had been a store demo and was like new. I had my reservations about it, with its plastic body and plastic lens mount and all. It came with the kit 35-80 lens, which was actually surprisingly sharp (I had a lot of photos published using that lens). My wife was pregnant at the time and it was my desire to find her a camera that she could use easily, but also one that would be the basis for an EOS outfit that I could add stuff to. About the same time I bought the Rebel, I also bought a Canon 240EZ flash (Canon's top flash at the time) because the first model Rebel did not have a pop-up flash. That was a good move because the flash worked great on that little Rebel. That basic outfit got used a lot over the next 16 years, and never missed a lick. I finally decided that I'd like to get something a bit better, so I bought an EOS Elan IIe outfit. That was about eleven years ago, and it's still working perfectly. It doesn't get used as much now (my daughter's 26 and has moved out of the house), but it still gets used with family get-togethers when I feel like shooting film.
When I sold the Rebel on eBay, I got a whopping $20 for it. That is twice what I got for selling an Elan II on eBay at auction. The Elan II was like new. It had had maybe a couple of rolls of film put through it (it had been my mother's, so I knew how often it got used). So the irony here is I actually got more for a Rebel that was used a lot than I got for a "better" camera that hadn't been used at all. Moral to this story is these older Canon EOS cameras can be had for dirt cheap at auction if you're just patient enough.