The photos don't do a great job of showing it, and a lot of the skills in welding aren't immediately visible.
Welding joints that look good as-welded, instead of passing over it with a grinder and a coat of paint to cover up any imperfections? That needs decent skills.
Welding thin material, and not having the heat of the welding process just melt a hole right through? That's needs skill.
Welding thin material to thick material, where it's easy to blow a hole in the thin part before the thick part gets up to temperature? That needs skill.
Welding complex shapes where some of the work has to be done upside-down and you have to control what's going to happen to that molten metal under gravity? That's a special skill.
Doing continuous welds around complex shapes, where you have to keep the weld puddle in the right place and moving at a constant rate while completely repositioning your body and moving your feet? That's a special skill.
Because of thermal expansion/contraction, to get precision results you don't just put the parts in the desired location and weld them - you need special 'fixturing' that anticipates the inevitable change of shape due to the heat of welding. That's a special skill.
Welding joints where, to prevent contamination, you need to get shielding gas not only at the front of the joint but also at the back? That's a special skill.
Welding unusual metals, like special high temperature rocket nozzles might involve? That's a special skill.
And most importantly, if you're welding a part that takes 40 hours of welding and 39 hours in you slip on the pedal and ruin the part, you've lost loads of work. So a part that needs 40 hours of welding requires exceptional consistency too.
Of course none of this stuff is impossible. But for sure it's skilled work, and not easy to hire for.