Hmmm… Good question… So I’ll take a stab at it…
It’s super easy to make an awning out of any tarp and some tent poles. Some people buy the dining canopies which are essentially the same thing.
Most vandwellers are cheapskates because they’ve already been burned on a lot of expensive garbage, which also makes them gun shy.
VW was successful at selling both awning and tent kits. Screen rooms are a thing. One cheap product that fits all vans, and does all things could be a hit.
"Be the reason someone smiles today!" ~ Van_Dweller