Have you noticed that no one says "You're welcome" any more? Whether it be thanking the barista for a particularly foamy latte or thanking the mechanic for an efficient lube job, I've noticed that whenever I say "Thank you," I hear, "No problem."
The problem with "no problem" is that it's dismissive. When I've just spent $50 on movie tickets, and I thank the usher for tearing those tickets in half, I don't want to know that it's no problem. I want a little formulaic courtesy.
Call me a curmudgeon. That's what I get for being in my fifties, but I miss the little courtesies. "Welcome" is a term dating back 500 years, and it comes from the word "wilcuma" or "to take pleasure in hosting a guest." That's what social niceties are about. We don't throw out a "no problem mat." When someone moves into the neighborhood, we don't send the "no problem wagon."
"You're welcome" went out the door with the information age. No one thought to make up an emoticon for it. It took too long to say, and we discarded it, right alongside hand-written thank you notes, sitting down to dinner and tying actual bow ties. Among the Twitterati, we barely take time to write "THX."
It's like the phrase "my bad." We used to say "I'm sorry," which actually implied that we had sorrow for the action we had taken, and now we throw out "my bad" with the implicit understanding of "It's cool. Get over it."