Yes, the return on rooftop solar is way better than commercial solar.
Firstly, is saving a cost (which you would pay with after-tax money.) So as a saving, not income, the return is tax free.
Secondly homes buy electricity at retail rates (thus rooftop is effectively earning at retail rates) whereas commercial sells at wholesale rates, which is likely a small multiple. (And of course, being commercial, that income is taxed.)
Yes, in high-cost places (like the US) subsidies were necessary to foster the industry and get enough demand to get prices down. In other places the math makes sense without subsidies.
Incidentally it's a LOT easier to do 1000 rooftop installs than 1 solar farm. There's no planning, utility agreements, large scale financing etc. You just install and move on. A small team (4 people) can easily do 2 houses a week. With only one qualified electrician needed.