There's also quite a bit of research going on into different cell technology (https://en.wikipedia.org/wiki/Solar-cell_efficiency). The current physics wall puts it at about theoretical 4-fold increase in electricity per square meter compared to what we have today without consideration of the cost of manufacturing or longevity, which is expected to again, continue to improve.
Also as far as land goes, people are really bad thinking at scale. If you look here: https://www.seia.org/research-resources/major-solar-projects... you'll see all the installations and the ones planned. The sun doesn't shine every place, on every day, sure, but when you have that kind of coverage it's a different story.
There's a lot of arid desert out there and lots of potential for combining solar panels with existing food farms through something called agrivoltaics: https://en.wikipedia.org/wiki/Agrivoltaics ... many crops do as good or better with shade so this is just a straight increase in profit per acre for those crops with the dual use of energy generation.
This is all pretty new. The cost tipping points in favor of solar just happened a few years ago. We're seeing one of Clayton Christensen's graph of disruptive technology in real-time right now (see https://en.wikipedia.org/wiki/Levelized_cost_of_electricity where solar went from being the most to the least expensive in about a 5 year period)
Everything hits a physics wall, of course but not only does it look like there's still plenty of runway with solar before we get there but there's also lots of unexplored opportunities such as, just throwing this out there, a solar capturing wind turbine that can cleverly capture energy both ways. The point is this is still extremely greenfield