Politicians and lawyers are paid well enough and then some for us the people to expect due diligence, especially for such an important piece of legislation that's to be in effect for the foreseeable future.
The median UK salary is around £30,000.
MPs who become part of the government often do fairly well out of it, obviously more so the more senior the government position(s) they hold, and there are a lot more members of the government than most people realise. But rank and file MPs often get a pretty raw deal compared to the kinds of alternative options anyone with the attributes to be a good MP would probably have.
https://5050parliament.co.uk/get-elected/
Maybe we'd be better off if MPs had to study and practise as much as an NHS consultant has to before they can run the country?
"Isn't that high" is not with reference to the median, but with reference to their pre-existing career prospects.
The salary of MPs is not sufficient, by a long way, to attract almost any one from other competing careers.
(I don’t have a solution, every option I’ve heard comes with downsides)