We have a lot of unused land that could be filled with solar panels: rooftops. Until every suitable roof is plastered with them, I don't think that we have a land issue. Similarly for wind, the problem is not that we don't have the land, the problem is NIMBYs that don't want turbines to "ruin their view".
The cost of solar panels themselves is proportional to the surface area, but the cost of installation has to take into account the administrative units because they impact wiring and other equipment. Residential rooftops are thus the ideal surface area if reducing cost is your main metric. There are other reasons, such as decentralization, for which this kind of deployment is interesting.
So I don't disagree with any of what you've said. I'm glad you brought up decentralization, because that's what I think many people actually want. I can't run a nuclear reactor in my back yard, but I could put panels on my roof. In doing so, I'd be somewhat insured against blackouts, "the crap hitting the fan" or whatever else, as well as not writing a huge check each month to the power company.
Some research[1] indicates that solar panels on most roofs could cover about 40% of the US's current power consumption, although the variance is fairly high (California could cover about 74% of its power demand, while Wyoming could cover only 14%). I think 40% would be a great improvement, particularly if it's fairly efficient and not too expensive; I just think we should be open to using things like nuclear for the other 60%+.
