"THE LION KING, ALADDIN and HARRY POTTER are on solid footing. Are the numbers simply such that Broadway can't sustain more than about 3 'kid friendly' shows at any one time?"
I thin there is a limit to how many of those kinds of shows the market will support at any one time. But also, in my opinion, FROZEN and ANASTASIA are really not good shows, so I think word of mouth might have something to do with their relatively poor performance. If there were five or more really great kid-friendly shows running on Broadway at any one time, they might all be doing well. But also, aren't there more kid-friendly hits on Broadway right now than the ones you mentioned? Doesn't WICKED count, for example?