I have four Glocks (17, 19, 21, 26). They are all basically the same. Known reliability is good, performance good, everything good. But still less than 50 years old and yet unproven with the test of time.
There are Glocks out there that done over a 100,000 round that is with standing the test well. Their frames well not rust away like a steel one well.
Pistols like any machinery has a left expectancy. If one doesn’t use it that is a very long time, If one uses them they well wear out.
Even though I am a huge 1911 fan, the Glock 19 would make a good backup gun in the field.