I absolutely agree about the reliability of the Glock, especially the Models 17 and 19. I believe the reliability and success of the Glock legitimized this genre of handgun.
But I'll disagree that the Glock's reliability is what put this gun in to LE holsters across this nation. A contributing factor for sure, but it was the irrationally beyond "competitive" contracts that Glock gave to ensure the popularity of these pistols.
LE organizations had major incentives to transition to the Glock. Glock's infiltration of the police market in the US was probably a bigger accomplishment than their handgun was.