That's true, but some of it comes from how people are formed. And some of it is cultural. In the "Old Country" in the days before radio and television the church was the center of the village and the center of people's lives. Lots of competition today. I know parents who attend Saturday evening liturgy so that their kids can play sports on Sunday mornings. And then, of course, one should keep in mind that 15 minutes is long for a badly-celebrated, badly-sung liturgy while 90 minutes is not too long for a well-celebrated, well-sung liturgy.
There are lots of other factors, too. A friend of mine who is a RC priest celebrates Vespers for most feast days. For the first 3 or 4 years he only had a handful. Eventually people began to love Vespers, and now he gets 30-40 (small parish, about 400 on a weekend). This priest loves to pray, and is happy if only 1 or 2 people join him. But lots of priests are so busy with the administrative part of their job that prayer often gets put to second place. Or they wind up thinking that it's not worth it unless they get a good crowd.