Google does update its forecast more frequently, and usually is as accurate as the others for the hour ahead. And the longer range 3+ day forecasts aren't noticeably worse either. It's just the intermediate 4 - 48 hour stuff that they're surprisingly terrible with, but that's exactly the time period I most care about in everyday use!
It really does come down to data source quality and access…that’s the crux of it.
Other apps have a different government?
If you use Google 99% of the time and only check other apps when Google is wrong, then that's a biased experiments.
I pull weather data from multiple apps all the time because I’m a weather nerd and they all agree equally poorly.