"Celtic have outgrown this parish. It’s time we looked at more viable and professional alternatives."
Historically speaking, it seems that Celtic has been the horse drawing Scottish football's cart for quite some time now, most of the time being abused by those who think they're driving the cart. I don't have the data in front of me, but I'm going to guess that home attendance for clubs like Hamilton and Ross County spikes significantly when Celtic plays there, as opposed to, say, when Kilmarnock or Motherwell visit.
Without that boost of income, those clubs will definitely suffer. Arguably, some clubs and even the SPFL itself could go under without Celtic.
That said, I would hope that the dynamic that Celtic carries this league is not lost on the rest of the clubs, and Celtic's reach internationally -- especially outside of the UK and Europe -- is not ignored.
Niall J hit the nail on the head with this article, and it may be time to move on. It will be interesting to see whether the other clubs, or the governing body, moves to try to keep us here.
Thanks, Niall!