The Republicans have become a party that's all about style, not substance. That was politically useful in the Obama years, when all that was needed to keep the base in line was to take the leading role in the Two Minute Hate. They were great at organizing symbolic Obamacare repeal votes and symbolic "investigations" that everyone knew didn't actually matter. But they've lost track of how to actually govern.
I suspect part of the reason is because of what happened in the Bush years. For the first time in generations they had both houses of Congress, and the presidency, and the majority on the Supreme Court, and so they were able to get their way, without having to compromise with the Democrats. This gave their ideas the unfettered test run they'd never really had before. Major parts of the New Deal were repealed (good-bye PUHCA). Private-sector innovation proceeded without new regulatory curbs (e.g., the way the shadow banking system flourished with mortgages packaged up, tranched, insured, and securitized). They got the war they'd spent years itching for in the Middle East, and the monster increases to the military budget, and big upper-class tax cuts, and the roll-back of gun regulations, and all their favorite people in charge of defense and security, etc. Only, it didn't turn out like they expected.
By 2008, most things in America were noticeably worse than they'd been in 2000. Unemployment and poverty were much higher, incomes and stock values were much lower, the Middle East had devolved into a bloody quagmire, New Orleans was a soggy shadow of its former self, lower Manhattan was a ruin, Bin Laden was running free, US credibility was shattered, the nation was in the midst of the worst recession since the Great Recession, credit markets were frozen, etc. Even in the few areas where things hadn't actually gotten worse, they'd gone through eight years of relative stagnation, compared to the rapid improvements in the pre- and post-Bush eras (e.g., murder rates effectively holding steady under Bush, compared to declines under Clinton and Obama).
When you get everything you've been calling for, and the results are drastically terrible, it's got to make you a bit gun-shy. I think that's why the Republicans have come to focus exclusively on what they're good at (getting gullible people to hate whoever the Democratic enemy-of-the-moment is), rather than what they're bad at (enacting effective policies).