Actually, George W Bush signed the spending bills for 2009. But the central point remains that conservatives (Republicans) hold no claim to fiscal conservatism.
I think we're misunderstanding each other. Yes, of course conservatives claim fiscal conservatism. But when I say they hold no claim, it's an almost archaic phrase meaning yeah, they can say it but don't actually own the claim.
Bluntly, according to their record, conservatives are not fiscal conservatives. They just dress that way.
Trump is essentially a European right-wing populist, something that hasn't really existed in America before.