It is theorized that desert planets might be rather common https://en.m.wikipedia.org/wiki/Desert_planet
So it makes sense to have lots of them.Get your astronomy outta here, this is a space wizard series.
Take your pick then;
Sci-Fi explanation or plot explanation.
As mentioned earlier, SW is very influenced by Westerns, and Han is very much the gunslinger of the OT, so a desert world works well that way. And, it makes sense to “return” to Tatooine considering Han’s past with Jabba.
Plus, how many environments are there left to pick from anyway? The speeder footage suggest a city or industrial area, so we might finally get to see Corellian.