Best ways to keep RV cool inside in desert climate

Interesting ideas, BUT why are we seeing more DARK COLORED RV units today? Years back they were mostly white with colored graphics. You would think that the majority of RV use is in the summer months, so why are we seeing these dark colors. They are heat sinks. They look sharp, but are not practical. Even if you head to the sun belt in the winter, It still is hot most of the time.
Just my thoughts.