Interest rates can't go lower. Taxes can't go higher. Neither consumer nor Ontario government debt can go higher. Only one thing could go higher, and that was federal deficits- but Trudeau already did that, with his $30 billion deficits instead of the promised $10 billion. More regulation might work, but might also create conditions that later backfire (like BC's government mortgage assistance, which can only create more demand.) "Less regulation" is not in Wynne's vocabulary.
My guess is that somewhere along the line we will see more bonds printed, and a little further down the line Ontario's debt downgraded another couple of notches to junk bond status, with the commensurate increase in interest rates on that debt. That appears the most likely scenario.