>>As a sport, why is lacrosse not more popular than basketball?
Lacrosse is a Spring sport at the HS and college level.
The better question is, Why is lacrosse not more popular than soccer?
It has contact, scoring, and requires opposable thumbs.
Basketball was invented for the purpose of having a game to play when the weather is bad outside.
I don't know about the north, but in small town Texas, the kids go from football to basketball (football is king, so the schools in the football playoffs cancel their basketball games as long as football season is going on), and you play basketball until the spring sports, which are track, weightlifting and baseball. There just isn't really room for another outside sport on the schedule, particularly one that is equipment intensive.
Lacrosse doesn't have a great name. If it was called Whack! or something, a lot of guys would go out for it.