@taco heat-pump systems are not huge users of electricity, usually on a 20A or 15A circuit.
A more realistic threat to grids is 80A EV chargers.
Both are going to happen.
Provincial regulators just need to change some regulations to prevent utilities from charging infrastructure like transformer upgrades to any residential property that's requesting a normal 200A or 300A service. The upgrade costs have to go into the system as a whole.