This has already started to a degree, as people trying to build net-zero homes find that at a certain point the cost (in money/effort/carbon/energy) to add further insulation exceeds the cost of adding heat to the home via adding solar PV. I believe retro-fits of older homes hit this point earlier, since it can be harder to insulate them beyond the low hanging fruit.

Obviously as PV price continues to drop, this point will be met earlier and earlier.

Ive observed this already in off-grid situation where the priorities are different (no net metering, power not used/stored is power abandoned) but when it hits the mainstream it could make a real dent in home construction/insulation biz.

But you need to build more solar panels. So the question is whether it'll be cheaper to insulate better, or to manufacture more solar panels.

I think the idea that energy would be cheap forever is what got us into the current mess of high utility bills for poorly insulated homes.

I doubt that will ever happen. 1) Insulation is essentially passive for the lifespan of a building, PVs and other solar tech + associated heating & cooling systems need regular maintenance, cleaning, replacing etc. 2)highly energy efficient buildings provide better comfort and indoor environmental conditions than a poorly performing building with lots of active heating / cooling etc. 3) insulation works day and night, all year round, PV only produced electricity when the sun shines. There is a big gap between what PV can supply and day/night demand and summer/winter demand. Storage might get to the point where it can bridge the day/night supply/demand gap, but seems unlikely to bridge the summer/winter supply/demand gap.