The bigger thing, at least among my friend group, is that some people will take a pay cut to work on something interesting/avoid doing CRUD work/etc. I feel like that's the most common reason a EE is willing to accept lower pay, though I've also generally felt that the bulk of EE jobs were in lower cost areas than the Bay or NYC, so it would be interesting to see a breakdown of EE salary by location and compare that to pure software.