How does that apply here? In fact, the opposite would seem to be the case; the fewer people that install solar panels, the more expensive electricity is to buy off the grid, meaning the faster the payoff time for a home solar system.
If you build a new house with solar integrated, the person who buys the house (and society generally) benefits over time, but they need to pay up front for the costs. If you add it, then people will buy the other "cheaper" house that will cost them more in the long term and you'll go out of business. This is called a "Race to the bottom".
Pretty much every nation has a whole bunch of regulations about what you can build and sell, and what kind of houses is a popular specific example everyone is familiar with, not because they're all secret authoritarians, but because in the past, people did a whole bunch of stupid, short-sighted things to hit a lower price point and the businesses that didn't do stupid, short sighted things couldn't compete with them and were forced into doing stuff they knew was stupid or dangerous and people ended up living in dangerous, hard to heat homes.
This is the core problem of climate change. We'd all be better off dealing with it, but if someone else goes for the short term profit they ruin it for everyone.
It's a time-value-of-money problem. Over the long run, solar saves money. The payback period of our panels was about 9 years, but our utility raised their rates, so I think it's more like 7 now. Problem is, most people don't have 7 years worth of utility bills available to spend now, and if they did, they'd rather spend it on other things.