1911=super tight tolerances=zero room for error
Glock=loose tolerances and simple design=consistent reliability
It has taken 100 years to perfect the 1911 platform, as for Glocks, less than 20. I'm done.
A rather severe oversimplification. 1911s had absolutely nothing but a stellar reputation for reliability until a few decades ago, at which time a few things emerged:
1) The military's horrible maintenance (refusing to keep track of spring changes, mixing and matching parts as guns wore out) had left them with a lot of very bruised and bloodied pistols, which were falling apart, and did not AT ALL represent what the factories had sent out originally.
2) A new generation of pistoleers who'd never been in a single gunfight, but sure read a lot of magazines, determined that you needed your auto to run hollowpoints, something the 1911 was not originally designed to do, and needed some tweaking to get there.
3) Colt, under their dozenth (or so) group of owners, had largely started riding their legendary name and not caring what they put their name on as long as they could get money for it. Their tolerances loosened, their QC went to hell (oops! forgot to heat treat those parts...) and suddenly a platform which had worked for 3/4 of a century began to have trouble. In stepped Kimber, undercutting their price and exceeding The Pony's quality, and the race was on! 1911s were hot again! So everybody started making them, and it has taken some growing pains for all of these outfits to figure out how to make it run right with +P/standard ammo, 185-230 grain bullets, twenty different shapes of hollowpoints, etc. All things which, again, the original pistol was not designed to contend with.
Glock has done well, no doubt about it. Of course, their ergonomics are...
interesting for lots of shooters, and they are some of the biggest jerks on the planet to deal with if you ever dare to have a problem with your gun, but there's no doubt about it: after Browning invented the tilting breech semi-automatic fired via striker, and with the benefit of modern materials and manufacturing techniques, the Austrians did a darn fine job.