Plenty of RVs have rooftop solar panels that'll routinely travel at 65 mph into a 35 mph headwind with no trouble. They're mounted with just plenty of little L-brackets screwed into essentially a plywood roof. Usually an RV roof has lightweight metal struts underneath for load support, but that's not what the solar panels mount to, that's mostly to carry the weight of a person standing on the roof. Never heard anyone have wind shear issues, the only trouble the L-brackets cause is water intrusion when the caulk ages and fails.

Solar panel weighs like 50 lbs. Think of it as a sheet of plywood. Not only do have to support the weight but have to worry about the wind load.

You can use wood, but then you have buy good amount of treated lumber and put it together. Galvanized steel also lasts longer than wood.

My impression is that galvanized steel fences are cheaper than wood ones. Even using steel posts and wood panels. People make wooden fences cause prefer the look.

I would guess that a lot of the structure is needed for wind load rather than the weight. And weight could increase with s ow cover.