I'm not sure it is really laziness rather than learned convention. And I think we all have things in our pronunciation which aren't quite accurate, but are convention in our accents.
One of my bug-bears (which comes from my Scottish mother) is the inability to indicate through pronunciation the difference between 'where' and 'wear' and that 'law' has no 'r' in it unlike 'lore' etc.
All of these are in one regard sloppiness or laziness, yet they are, in reality, merely conventions within certain accents.
The 'where and wear' thing may be a hangover from the Scots.
Every effort in my younger days was made to expunge Scots language from the schools, and sometimes, children were actually belted by the injudicious use of the 'tawse', for using words such as 'Aye', 'richt', 'enou', and, instead of the English 'where', 'whaur'.
These, and many similar words, were dismissed as colloqualisms or slang, when their provenance can be traced back eight centuries and more as Scots split from what was to become English.