Inertia must be incredibly strong. Otherwise, why did it take so long to come up with something that strikingly simple? The last time someone allegedly had an idea like that was around 212 B.C., in the defense of Syracuse.
It didn't? There are both solar ovens and solar power plants in active use.
The issue's mostly that it's historically been fairly inefficient and expensive (compared to other electricity production sources). Prices have been coming down through improved efficiency and economies of scale, the plants being built these days are bid under $75/MWh and construction has been ramping up a lot especially in high-irradiation locations e.g. Morocco onlined their first station in 2017 (510MW CSP, 72MW PV) and is already building a second one, and Dubai is apparently aiming for 5GW installed by 2030.
CSP requires a large investment compared to PV solar, as it needs to be done at scale to make coolant systems, towers, turbines and generators cost effective. It needs its own large allocation of land, rather than be distributed. It also, like PV solar, has poor temporal availability, so compares badly to fossil fuels, nuclear and hydro.
It has potential to be cheaper than PV, and integrate well with thermal energy storage. It could also be more efficient, if the temperature can be increased (due to Carnot efficiency). However, the convenience and falling prices of PV panels may prevent CSP becoming popular.