It's not just compensation. Compensation for electricians is quite high already - the problem is the ramp up to those levels is long tedious and hard.
Pay for apprentices is abysmally low - honestly, it's not much above McDonalds, and the physical strain and effort of the work is similar, if not more. (Which is why "join a trade" is not quite a solution - most trades are physically demanding jobs and unless you start in your 20s, you won't be able to do it in your 40s. But by then you should have enough to either be leading a bunch of apprentices or running your own business).
Also, the historic demand for transformers, breakers, and other such equipment has usually been sufficient to keep the few companies in business. If there's worldwide demand for say, 12 mega transformers a year, and everyone has surge capacity to produce say, 15 transformers a year, you don't invest in a new factory because demand is unlikely to change. Things like AI datacenters and such have driven the demand up - but it takes years to bring on new factories and they'd want a solid order book confirmed before they invest millions to make 15 transformers a year because if demand drops back down to 12, you're screwed because now you have a factory that isn't being used. And this stuff is custom manufactured so you can't even make a spare.
It's why Airbus and Boeing have 5-7+ years of orders for new aircraft (and likely closer to 10 for both). Ditto things like fabs - ASML is the only company to make it not because they're the only ones that can do it, but because they fill worldwide demand. A competitor starting up will need to make a case for competing in a segment where current production satisfies demand and future demand will not only increase, but stay increased to keep both companies viable because if demand suddenly drops, then it can be hard to get a return.
Right now the lead time on many parts is in the 4-5 year range, and it's hung around that for the past 4-5 years now showing production and demand is basically steady. Someone might be able to produce more but then orders are going to run out and now you've got no customers because you've emptied the queue.