Mech E here. The reality we’re paid less is because it’s harder to make a profit (but to be fair, MechE in tech get paid well still). Making good margins is really hard. You have one shot to do anything. Worse of all, anyone can take apart your design, reverse engineer and sell your product by 20% less because they don’t have to worry about recovering R&D. Most Americans won’t even bat an eye, they’ll just buy whatev…
Software companies have very little cost other than engineering.
For hardware, once your engineers have created a design, you still have to operate a factory, pay for expensive manufacturing equipment and expensive labor required to actually build the design.
Thus, you get much less "margin per engineer" and the available portion of gross margin that can be paid to engineering is much smaller.
Still, thank you OP. It's nice to get some recognition sometimes :)