It is probably cheaper to do Solar PV due to unit economics rather than overall system efficiency. There's been a lot written on learning curves and wright's law, but rate of improvement is driven by design complexity and need for customization. Concentrating solar is both more complicated and needs more site customization, whereas solar pv modules are simpler and fly out of factories by the millions.

This is a wonderful table: https://substackcdn.com/image/fetch/w_1456,c_limit,f_webp,q_...

From this post: https://www.volts.wtf/p/which-technologies-get-cheaper-over