What region of the US are you in. I have lived in the south east, Midwest, NY, CA, TX and vans are the norm for most trade jobs outside of landscaping or jobs that can actually benefit from an open bed. HVAC, plumbing, electricians and the like all have equipment that is a lot easier to organize and safely store inside of a van. Now sometimes depending on the type of work that person does they may opt for a high roof and I have seen some opt for the chassis cab and go with a third party body that gives even more room but still enclosed and may even choose the van chassis.
I am quite surprised to hear you have never seen an electrician use a van. That said there are certainly specialities where it’s more common.
90% of trade work is all on pavement and trucks suck for tools. If you are a logger yeah sure you may be using a truck to get to your equipment, similarly for lineman but for the vast majority of trade jobs companies opt for commercial vans. You are describing trade work like it’s the tv show landman.
They absolutely are for consumers but not so much in business. Vans are superior for most trade jobs within the US and pretty big sellers. Yes there are some gaps like if you in parts of Alaska or other very rural parts of America but largely trade jobs are spending all of their time on pavement.
I've never seen or known a trademan that drove a van. They all drive pickups. Maybe this is a regional thing.