If subsidies were stopped on solar, geothermal would make the most sense outside of a place like Arizona or S. California where the sun shines 90% or so of the time days. Both would be a killer combo. I suppose some people would eschew panels over the issue of fear of a fire or they are simply buttugly. But to me, in areas where solar panels are less efficient and energy costs are low, superinsulation and geothermal are a far better investment...they just don't get the tax break.
Ultimately what happens when everyone is on solar and the utility is losing money? How will the pay structure have to change? The "wholesale" price will have to drop to near zero, eliminating a lot of the "income" from solar panels.