As a member of the GOP, you stand a better chance of booting out an elected Republican whose politics you don't like and impacting the Party to move in your direction, than you would trying to get an elected Democrat to come around to your way of thinking.
You can't accomplish either thing by leaving the Party system.
You can also work and support a third Party, and you will feel good about yourself...but that's all you'll accomplish in the real world, other than perhaps help get Democrats elected.
If you can't understand something that basic, you will never understand Party politics.
Or politics for that matter.
Dude, I worked for the Republicans when I lived in Arkansas, and again in GA in 2000. Might be some good people working for the party, but not among the folks running it. The folks in charge are power mongers pure and simple, and ain't interested in hearin' what you have to say. Their response is similar to yours - party first and "where else ya gonna go?" Just do the work, give 'em money and shut up.
Well, the answer is, I'll go home. Gridlock is more desirable than the current state of affairs and the Republicans seem to pay more attention to their conservative base when they're out of power. In the mean time, to hell with 'em. If the party doesn't stick to principle, it ain't my party.