If you give the money to the consumer level for every $.40 the government spends, the consumer adds $.60, often borrowed and payed back with interest to a local bank, they employ local contractors to first put on a new roof if the panels are going on the roof, cut down trees etc. The contractor then installs proven technology purchased from companies they feel are stable and will give their customers support for years to come. With the solar panels in place the customer decides that a heat pump would be a better choice than their old oil or gas fired boiler or furnace and again they call in a local contractor to come and install a new high efficiency heating/cooling heatpump unit to replace a low efficiency A/C unit, better insulation, a heat pump water heater, possibly new windows to allow their new system the best possible chance of keeping their home within their new solar capacity (solar capacity is based on home history so to change the heater from fossil fuel means economizing on electrical use where ever else possible). As far as electrical use goes the new solar system owner is concerned with tracking how their system is going and buys efficient lighting, efficient appliances, and checks their ratings for generation and electrical use almost daily, how many people without solar do that?
I personally have a 8.8 kW grid tied PV solar array. I read my meter every morning. I check my solar production every week. In two years I have spent only $130 dollars on grid electricity and $25 on home heating oil (our oil boiler is our backup stage for our heat pump).
No it does not allow the grid to reduce its capacity any because the base is still required, however during the sunniest hottest days when brownouts and supplemental power, usually provided by bringing additional coal plants online, are required, my solar array is giving back into the grid nearly 50 kW a day, the equivalence of several houses additional usage during those times.
All of that puts thousands of dollars into the economy at the local level and the money moves up to the ladder to the manufacturing and research level by sales of technology that is functional.