I must be reading things differently because I agree with almost everything you say in this post (more in a minute) but when I read Rimbaud's post I was thinking 'yeah, that's optimistic mate'.
Because...
It's a moveable feast of delicate balancing act - the deeper they go, and the longer they stay, the more damage they do to to Putin, but the deeper they go, and the longer they stay, the more likely they'll be destroyed. That would give Russia a huge psychological/propaganda victory, it would have a huge negative effect on Ukrainian morale, and it would cause serious questions to be asked throughout NATO on the wisdom of supporting Ukraine if it's just going to throw away it's people, it's gear, and it's victories in ill-considered, overly ambitious/deranged operations.
t's knowing when to quit, and what battles you win by running away from...
That bit is right, and the time to move out is now. Unless you want to give Russia that propaganda victory and serious questions asked in NATO.
But...
The win however of diverting huge parts of the Ru force that's battering the fuck out of the Öst Front, and making Ru use half it's army chasing ghosts, is a win well worth playing for...
Half their army? Really? It's half? You're the expert, genuine question.
And if it isn't (and I don't think it will be), then it's an inevitable 'win' for Russia.