Its the same magic where these "moderates" appear and don't end up completely compromised by their time in politics and don't end up doing irreparable damage while you wait for that "replacement" to kick in. A single gun control law passing that most "sensible and moderate" Dems approve of would still set us back possibly indefinitely, same with plenty of other non-extremist only positions of the Left.

Your point isn't hard to understand. Its just based on a lot of hopes and dreams of the best possible outcomes to function.