Hi, sorry but wrong on both accounts..
The only washes that contain wax are the cheap & nasty variety, proper detailing product companies do not do wash/wax.........they do however make detailing spays that can top up your wax as a final stage after washing.
Glass is not smooth (at a microscopic level) and water pools on it without a product such as Rain X.
Rain X does not need to be constantly applied if done properly the first time.
I applied Rain X to all my glass (after a thorough clean) last July - water still forms tight beads
and flies straight off as soon as you move.
Personally I like to be able to see out of my windscreen when it rains......
Cheers, Geoff.