I just saw Chris Tucker live a couple weeks ago for stand up. A lot of his stuff centered around the fact that he's in trouble with the tax man.
He also brought up doing another rush hour. Asked the crowd if they wanted another crowd went crazy and he was like so do I go ask Warner brothers about it. (I think that was the studio,or paramount, I don't remember)
You would think with such huge paydays any actor would just jump the chance for a sequel for a guaranteed payday, but for Jackie, it really isn't about the money as he makes like over $50 million a year, so he literally can just keep declining the offers for his own projects.
Chris through, I would imagine is an instant yes from the get go.
That being said, I miss seeing Jackie and Chris onscreen together and will be there day one in theaters.
I still dream of that from time to time. Shanghai Knights is said Jackie at one time to be Jackie's favorite American production, and as a long time Jackie Chan fan, long long before Rush Hour was a thing, it's so easy to see why as the action fight choreography and set pieces are a stratosphere above anything in the Rush Hour series.