FougaMagister. Firstly, you are breaking the law by listening to a scanner.
Having spent my life as a controller (two international airports, 1 ATCC and two light aircraft fields) I would agree that there are occasional lapses on both sides. However, the vast majority (99.999%) of professional airline/ helicopter/ air taxi pilots I dealt with were very good and kept to standard phraseology. Let's face it, in a very busy environment you have to! However, the R/T from many private pilots could have done with improvement. Maybe this stems from a) poor training (do any potential PPLs get simulator time before operating live R/T?) and b) poor R/T from their home "ATC" unit. I have heard terrible R/T from some AFISOs and ATCOs at small training airfields, yet these are the people who should be ultra-strict with their procedures so that trainee pilots learn correct R/T from square 1.
Lastly, professional ATCOs (I don't know about AFISOs) have their R/T procedure regularly checked so they are encouraged to "stay-standard".