Honestly, my usual experience with Starbucks you have to wait in lines.
I do travel mostly in the Western US, and hit some Starbucks stores that generally are busy, except, in the evening
at some locations where business activity dwindles.
I have been to the original Starbucks store at Pike's Market in downtown Seattle, and that place has a line out the door all day long.
Well, that would be for obvious reason, as there are so many tourists there too.
This fad as you say has children that grow up and become regulars eventually as they develop a taste for the drinks too.
Every year how many million kids hit coffee drinking age and start the Starbuck addiction, or whatever it may be?
The stores I go to have slowed way down. Something I have noticed at every SBUX store I go to, black teenagers and black women go inside the stores and get free cups of ice water. I was forced to wait while the barrista serviced the moochers. When it was finally my turn to order, I too ordered a free water. Everyone should go in and just order a free water so they stop this wasteful practice. This costs the shareholders in terms of inconveniencing paying customers and wasted money on cups/lids/straws. Plus it adds to the landfill.