I have a Glock 17 thats going to pass 60000 rounds sometime this winter. I also have a Glock 26 thats headed for 30000 rounds. I really cant say how long they went without some sort of stoppage, but generally, they run without issue, and the stoppages are actually not a common thing. They both have had ammo/reload related issues/stoppages at some point, as have ALL my guns, including my revolvers. Really no other issues/failures other than that, at least with guns known to be reliable otherwise.
No matter what, if you shoot a lot, youre going to have things happen, I dont care who makes the gun.
Ammo and mags are usually your weak link and problems related to them are an inevitability if you shoot regularly.
Hygiene can be an issue here as well. I am truly amazed sometimes at how many people dont clean their guns.
Most of my ammo related issues or stoppages are due to worn out brass (I load my brass to failure, and it gets reloaded a lot), especially the case rims in the autos, and the case mouths/necks in the revolvers. With the autos, "most" dont stop the gun from functioning, but I do get an occasional stove pipe or fail to extract with them, which is usually solved with a TRB.
My revolvers tend to be more of a problem when there is a problem, and theres usually more work and/or focus required to get it back in action, and many times, its required tools to solve it.
Personally, if I go by failures per round fired, Ive found the autos to be the more reliable of the two, and the one less likely to go completely down when there is a stoppage.