That's very likely part of it, electronics can be knocked up in a Chinese shed by robots and low paid people and don't cost a lot to ship.
Actual metal bashing needs more man-hours and is still done in the UK occasionally. Too heavy and bulky to freight at low cost.
Having said which there's probably a massive mark-up on a boiler when you see how much more metal you get in some agricultural machinery which doesn't cost much more.