even if this is the case (and again, I expect the "status quo" is to not cap spending on social programs so it's still a loss), the GOP is still getting a win if they get to increase spending on what they want while capping things dems want.
They folded earlier in the day, hence the rally. Biden is an Establishment player, he's not going to cut military spending as the fiscal multiplier associated with it provides a floor under the economy going into an election year.