Fiscal conservatives think the deficit and debts are a real issue for the country's future. They just don't make up enough of the GOP to matter anymore.

The GOP (and the Dems) don't really look past their next elections so they're not incentivized to do anything about these issues. The GOP will play lip service to it, like you said, to undercut Dem ideas or to win some fiscal conservative votes but they're not really going to take the drastic cuts needed across the board.