There was plenty of 2- and 3-finger picking of 5-string banjos before Earl Scruggs! (Though not "Scruggs-style", of course.) People played 5-strings in any way that came to them. (Aside from the whole parlor classical scene.) It seems that playing styles went through a bit of a bottleneck during the revival, but things are becoming somewhat more varied nowadays, in search of both old and new ways of playing, c.f. the interest in jigs... ;-)

There's also the theory that southern old-time playing is more based in the Scottish than the Irish tradition, thus reels rather than jigs... I'm personally no scholar in that line.

~ Becky in Tucson