> Increases the cost of homes
In a narrow sense; TCO, however, may be lower. (EDIT: TFA itself indicates +$9500 new home cost, -$19,000 30-year electricity cost as the average impact.)
> Gives solar power industry a boost in a way that's hard to get rid of--they will lobby to keep this even if other industries are around and it'll probably never change
Sure, the solar lobby will seek to preserve this as is as the landscape changes. Competing industries will seek either to remove or broaden it to accommodate other approaches to the same policy objective. The homebuilding industry lobbied against it, and it still was passed. “One industry will lobby to keep it” does not imply “it will never change”, or the past absence of the rule would never have changed.
> No incentive to research new energy technology in the meantime
Even with 100% residential solar deployment—not just on new construction—there’s a lot of energy demand that doesn't cover and plenty of incentive to find an efficient way of meeting that demand.