Maybe he does need to do that to prove a driver can do that because correct me if I'm wrong, but other than Big Schu and Hammie (and do single wins really count?), no championship-winning driver has ever found new -- and sustained -- success after leaving his team for another... right?
I would do the same thing if I was in his shoes.
It is to late for Red Bull to change things in better direction this season, and Verstappen always have championship ambitions.
I am sure other teams would stand in line offering him better deals than Red Bull, and there are much older guys in other teams, for example Lewis Hamilton and Fernando Alonso.
I've no idea what I'd do. Think when I was in my 20s, I'd have played (football) for free to represent even my state, never mind country. But I would probably need to pay for that privilege, given how shit I am as a player. Talentless and with the fitness of a person two decades older.
For us neutrals anyway, we'd love for someone to give that a try. I don't think drivers are beholden to team loyalty the way footballers are -- would love to see that sort of mixing up next season.