This is an English language phenomenon. In other languages r still sounds like a local R, s sounds like an S and t like a T. The glottal stop, which is basically a truncated grunt of sorts, has been endemic for many, many decades (perhaps centuries - I wasn't around) in some regions, certainly it has been widespread in large parts of Scotland. I noticed its spread onto the spoken media (radio / TV) in three or four decades ago, particularly in the name of Scotland (notice that those who don't use the glottal stop anywhere else will say Sco'land - a perceived conformity with the "natives"). Increasingly, it seems to me, aberrations in pronunciation (lore and order, coming sickth, etc.) have gained fashion appeal, the grunt included. The most extreme example of the grunt I have come across is ho' - 'el (where ' represents the stop/grunt - hotel to you and me).
I spent a few years in Western Africa where I came across pidginised English - native English may be headed in that direction. I think it is a sort of "cool" jargonation/distortion, not laziness.