What can be done in order to make solar energy more affordable so that more people can use it?
Government subsidies and more technological improvements.
Many governments provide a subsidy to homeowners so that they can purchase solar at a reasonable cost. For example, if a new solar installation might cost $10,000, the government might pay $1,000 or $2,000 so the net cost to you would be $8,000 (numbers are just hypothetical and real numbers vary from state to state or province to province).
The other way is for technological improvements to be made to solar so that costs can come down. Greater competition in the marketplace and more installations usually help bring about more efficient solar at reduced prices. For example, some companies are working on flexible solar panels that could in fact be installed on the outside of an entire building!