The government could best encourage solar by streamlining regulations,
The biggest thing they could do is change the regulations on their subsidies, tax breaks, and the like to replace the requirement "installed by a licensed contractor" to "installed in conformance with the applicable electrical code, permitted and inspected where applicable". This would allow do-it-yourself installations, where done properly, to receive the same benefits as professional installations.
The price difference between a homeowner-installed and a contractor-installed system is typically larger than the subsidies. So the current programs amount to welfare for the government-approved contractors rather than the homeowners.