That’s disingenuous - part of your compensation at many companies involves the expectation that the work is rewarding or its outcome has some non-monetary compensation. This is especially true in entertainment and media industries where workers will even be asked to work at a discount for the prestige.

Otherwise why do finance have to pay engineers more (at least here in London) or why are the interesting jobs nearly always paying below market?

If the show or film was cancelled after the worker signed a contract to work, the expectation of the worker when they signed up was that said work will see the light of day. Part of the compensation would be having the work on your CV etc and the prestige of your name on the credits.

The studio has reneged on an expectation the worker had when they accepted the contract and did not compensate them fairly for this new risk.

    > Otherwise why do finance have to pay engineers more (at least here in London)

Because of the demand and supply curve. If you require people in the city every day your hiring pool is less, if you require SC clearance your hiring pool is smaller, if you require some finance knowledge or experience of working on a trade floor then your hiring pool is smaller.

    > or why are the interesting jobs nearly always paying below market?

That’s not true, unless you refer to startups by “interesting” jobs and then part of the deal is equity with a chance to make the engineers retire 30 years earlier than normal workers. Not a risk worth for everyone but it’s there for those you want it.

The pool available to work in CoL is higher by virtue of London's insane demographics than pretty much every other area of the UK, and that stays true for quite some distance outside too due to the availability of public transport that actually works in that area.

For the second point I think you might need to re-read what GP defines as an interesting job, they specifically give broad examples but you've narrowed that down just to startups for some reason.