I got my first bow when I was 18 (I'm 48 now). I came from a non-hunting, non-gun family (it just wasn't something they did), so it was the easiest path to going hunting. Getting a gun would have been met with much more resistance. That said, I think the reasons for bowhunting's explosion of growth on the east coast (which may influence growth elsewhere in the country) are for the following reasons, in order:
1) More seasons. Ditto this for Muzzleloader. In Maryland, there's about two weeks total time for 'firearms' season. If you bow hunt or use a muzzzlestuffer (or both), your season is 5 months long.
2) More places you can use it. I've never lived in an area that I can hunt with a rifle. Shotgun only in firearms (or ML or bow). The population density precludes use of a long range weapon (or at least that's what our commie legislators have decided). Also, the standoff distance to hunt from occupied structures is dropping in many populated areas. Here, with a gun, its 150 yards. Many counties have dropped it to 50 yards with a bow. Exploding deer populations are driving this. Standoff safety distance significantly affects what properties you can hunt in a populated area.
3) The performance of bows jumped dramatically with the compound. And its increased since. In Maryland, a crossbow is also now legal and considered a bow. People can get profiecient much more quickly than they could with a recurve back in the 70's.
4) Once people are drawn to it by 1 &2, and develop skills rather easily, by 3, they're more likely to want to use it in more situations.
That said, when I get out west, it will be with a rifle, mostly because I don't want to be fighting the heat with a kill down, trying to beat the spoilage clock. Same goes here in the east. Even if its archery season, I don't hunt unless the temps are down. Just no fun hunting in the heat.