I still don't get why you think the (intended) profit-taking by renewables installers is supposed to be delegitimizing, nor do I understand why you focus on PV-installing homeowners only when Japan's feed-in law disfavours them (with the 10-year guarantee in place of the general 20-year one while the rate is the same, see upthread).

Regarding the explicit intention to give renewables installers good profits:

New feed-in tariff system a rush to get renewables in play | The Japan Times Online

There is a specific section in the new tariff law that calls on METI to aim for large-scale renewable energy use over the first three years of the new tariff. To accomplish this goal, the law adds, METI is supposed to give special consideration to the profits of renewable energy suppliers.

Thus it is hoped high tariffs will encourage large-scale investment by current and new players in the renewable energy field, especially since the internal rates of return under the new system range from 4 percent for some biomass forms to 13 percent for geothermal, 8 percent for wind farms over 20 kw, and between 3.2 and 6 percent for solar.