> If that's true, parliament seemingly doesn't want to win.
Aside from the Tories largely being aligned with the idea that you shouldn't be bound by environmental law (see sewage dumping), have to pay inheritance tax (they're considering scrapping it as an election boost), or not discriminate racially (pick whatever policy you want here), the kind of people who support the monarchy also tend to be rabid Tories - exactly the kind of people you don't want to antagonise if you want to stay in power.
A Corbyn government might well have gone against the monarchy. I can't see Starmer doing it, though.
The monarch is excluded from environmental law, inheritance tax, heck they can even racially discriminate in hiring. https://www.theguardian.com/uk-news/series/queens-consent