I don’t think they want to lose, but unlike the voters, they are willing to allow the Democrats continue to destroy America as we know it if they think it will set them up to control the treasury. By helping Democrats pass legislation, they are able to help their crony donor class with legislative hand-me-downs. Truth be told, I think they would much rather have the upper hand in spending so their donors would become more powerful, which would make them more powerful, and wealthy. I am sure they would rather let the Democrats try to win with the leftovers from Republican legislation.
Just saying, the minority party can help its crony donor class, probably close to as much as the majority party helps its crony class - keeping in mind that the crony class is indifferent as to which party is in charge.