Most of you forget that teams have 2 drivers - the one that tries to win the championship title and the second that helps him accomplish this goal.
Yes, definitely. I'm always trying to make this point, too. The aim at Mercedes is to a) win the constructors' championship, and b) win the driver's championship.
Compare Bottas with Rosberg. Rosberg was the faster driver, and more willing and able to fight with Hamilton. Bottas is the better team player.
Bottas is
good enough, and the chances of him and Hamilton going wheel to wheel and both crashing out of a race is far far less than it was with Ham/Rosberg.
Bottas is the perfect teammate.
The only time this changes is if Merc dominance drops and they are in a genuine fight for the championship. If say Hamilton is still winning races, but Red Bull are coming 2nd and 3rd each time and threatening for the constructors' title,
that's when it's time to consider replacing Bottas.
Bottas is doing his job greatly on Mercedes -all those seasons - and the only way that Russell is going to have chances of joining Mercedes will be if Hamilton announces his retirement...
Having said the above, we haven't considered other drivers' personalities. If Russell is faster than Bottas and crucially is also not going to be a Rosberg 2.0 and have conflict with Hamilton, then Russell replacing Bottas becomes a real option. Ultimately Mercedes will know Russell's personality and have a decent understanding of whether this is viable. But we need to remember that brute speed is not the only factor to consider. In a sport where there are two drivers per team, personality is key.