SevenSecSUV is right about the internals, even line assembly.
But what you get from the Blue and Red brands is dispatchable support techs, training, and domestically warehoused parts.
This is incredibly valuable in a business where downtime cost is high.
Also, most businesses really don't like the idea of their employees opening high energy, modestly high voltage equipment to troubleshoot via tap-a-talk and sketchy forum diagrams.
Real support carries a high labor cost, and some of that price will be carried into the physical product.
For the garagista and hobbyists, a benefit of paying that premium is that Blue and Red are probably doing a lot of component verification behind the scenes. In an age where even aircraft manufacturers can be duped by faux timkin bearings, I have leaned to trust no brand.
I would not buy another welder, Everlast or otherwise, without doing a lot of research including reviews, manual downloading, borrowing some arc time on one if possible, and opening the case on arrival to make sure the components advertised were the ones soldered.