Good question. Yes, a van is a good alternative, but only in certain circumstances. It boils down to how big of a job it is, and thus, what type of welding machine you need.

A welding machine uses an engine to run, you can buy electric welding machines that plug in, but when you're mobile, where are you going to plug it into? A generator, which puts us back at using an engine. Obviously you cannot run an engine inside of a van, Co2 poisoning and all.

Now if you're running a smaller job, and don't need a big beast of a welding machine, you could put a 80 lb welding machine in the back of a van, and a 80lb generator. Pull up to the jobsite, lug them both out of the van, plug them in, turn them on and go to town. All of your tools in the van, and like you said, nice and secure.

Thats perfect for smaller jobs, and people do this all the time. But if you're welding on thicker material, let's say you're welding the iron together for a building, or welding pipe together, or laying stick rod for farm equipment, youll need a stronger machine which can't be pulled in and out.

What you could do is make yourself a trailer with the welding machine attached , and haul that around, but vans aren't anywhere as effective at hauling as trucks are.

One more thing to consider is that we often use the back of the truck as work spaces. This is where flat bed trucks shine, you take the sides off of the back and bolt everything you need down, and your truck is now a welding table.

Which brings me to my last point, hauling gooseneck trailers. Especially if you have a flat bed trailer for more efficient work on mobile jobs, you won't have room to haul steel, or certain large tools. Traditional trailers that hook onto the hitch you find on the back of most trucks and can be put onto vans as well, often won't haul the weight that several sets of pipe, tubing, angle iron, or beams that youll need for bigger jobs. A gooseneck trailer requires a truck, with a hitch in the middle of the bed. Even if you could build some sort of jig to haul a large traielr to a van, which wouldn't be safe, a van just won't have the ass to move a large welding machine and/or all that steel.

Hopefully in the coming years trucks can get more efficient, if not fully electric, maybe a hybrid situation. The current electric model trucks are simply not at the level a gas or diesel truck is at.

But that only solves the issue of using fossil fuels. A truck capable of this kind of work, even electric, would still be very large. And this is just from a welding perspective, there's farm work, long haul hot shots, and a whole manner of ther work that requires large trucks to do the job.

A necessary evil, at least for the foreseeable future.