What about the massive massive rebates that were available a few years back to drive uptake? Not direct govt investment, but with a similar effect - people got some money back from the govt when they installed solar, then the govt mandated a high feed-in tariff for some years (has since dropped/been abolished)
That's still available for new installations, I believe. The feed-in tariffs have all but gone, but solar is still well worth getting purely for the reduction in power bills (especially if you can schedule the bulk of your energy usage to be during peak solar generating hours).
The flip side is that the power grid is now going into a death spiral where falling kWh sales are pushing up prices per kWh, making solar even more competitive, etc. etc. They're going to have to start charging a large flat rate for connection (which they can't do, politically) or the whole thing's going to fall in a heap within a decade.
The electricity grid needs to transition into an energy market kind of deal where their role is to balance supply and demand across the entire grid rather than a net flow in any direction.
Of course it'll never happen, the privatised incumbants will fight innovation tooth and nail to the grave like you say
