if you were in the states I could more easily answer, but maybe the answer is fairly universal anyway...
First, most baristas are trained by the previous idio... err... employee. Whatever they have been doing they pass on with whatever incorrect methods they added to it. The manager looks over his shoulder once or twice, and as long as there is a line at the counter and the till continues to be full, why fix what aint broken.
Of course, calling them baristas is wrong. We refer to them as the PBTC (person behind the counter). No more a barista than the fry cook at McDonalds is a chef.
And then there is the customer. Most have never had a proper cappuccino and would know one if they did. They would ask, "Where is the whipped cream?" or, "Why isnt there any nice foam on top? Dont you know how to make a cappuccino?" On this side of the hemisphere we blame it on *$$.
I make a proper cappuccino at home.. I know my wife knows the difference. But if someone came over and wanted stiff foam on their drink, Id put a lamb chop in their back pocket and release the hounds!
But seriously, the entire de-education in which the coffee chains here have participated has made it difficult, but it was one of the reasons I started my website. I try to assist and educate as many people as possible. "Paging Sisyphus... Call for Mr. Sisyphus."