RINO voters are a regional phenomenon. There are few conservatives in urban Maine, any more than there are in LA or New York City, and those up in the backwoods may not even vote. So you have Susan Collins. Urban coastal regions tend to be liberal. Rural and suburban regions tend to be conservative.
Yes. I have been to Maine. There are RINO politicians because of RINO and liberal voters. Collins is simply representing her liberal constituents. Our challenge is much deeper than complaining about politicians. We must educate and persuade voters and only then will they elect more conservative politicians.