I don’t know if the GOP caucus is more ideologically diverse than the Democratic one, but Democrats have more of a tendency to fall in line behind leadership than Republicans do. I think it comes back to Democrats believing in collectivism and Republicans individualism. Republicans elect people who got things done themselves. Democrats elect people who worked as part of a group.
Not passing the healthcare bill might’ve been the best thing to happen to the GOP. Sure, they’ll take a hit for not getting things done but that’s better than passing a bad bill. I'm not going to judge whether the Republican healthcare bill would be good or bad for America. That won't be important for the 2018 election. What will be is how the voters perceive the bill. Quinnipiac showed 17% in favor and 56% opposed. The Democratic healthcare bill wasn't that unpopular and that killed them at the polls in 2010.
Democrats didn't do that well in 2012 when people knew what was in the bill and did even worse in 2014 when people actually saw it implemented. The lesson should be that a major health insurance overhaul is more likely to go badly than go well. And the Republican plan take an entitlement away from some people. You can win by not giving an entitlement but you can't when you take one away. Republicans need to accept that Obamacare is here and any alternative would be replacing Obamacare. Democrats had the advantage of replacing nothing and that went bad for them. The best Republicans can do is change Obamacare using Republican ideas that'd make the law actually work. That'd be unpopular with the GOP base, but if the law is perceived as positive then people outside their base might like it.
There's a lesson here for Republicans and it's not one they want to hear. It extends to tax reform. Republicans believe in smaller government and you get there by lowering taxes. But here's the thing. The people paying most of the Federal income taxes are rich. The top 1% pays 46% of all Federal income taxes and the top 20% pay 85%. The top 1% "only" earn 17% of all income. So they pay a disproportionate share of income taxes. If Republicans lower income taxes the people who pay them, the top 20%, would get the benefit. You can't cut taxes for people who don't pay them.
And cutting taxes for the rich is unpopular. If you're cutting taxes for 20% of people the other 80% are going to be unhappy and the 80% will always have more votes than the 20%. Doing anything that helps wealthier people is going to make Republicans look bad and they'll suffer at the polls. And really rich people aren't complaining too much. At least publicly. This is heresy to some Republicans. They believe that cutting taxes is always a good idea. Republicans don't need to raise taxes. They can cut taxes but they better be able to sell that they aren't just cutting taxes for the rich.
Democrats are in the minority in congress because they didn't adapt their ideology to what the voter wanted. If Republicans fail to do that, they'll suffer in 2018.