Newt seems to have overlooked ‘term limits’ this time around...
I am of two minds on that issue. Being an elected official you do learn and grow with the job. Over time you get better at working within the system and understanding how things get done. You learn to build consensus and move the ball forward incrementally, which is often all you can do. Winning bit by bit takes time. Remember the Democrats held both Houses for several generations between FDR and Carter.
If you kick those guys out what you get is a very powerful bureaucracy against new and potentially naive legislators. I’ve seen it firsthand and let me tell you the bureaucracy wins every time. It’s their job.
At the same time I see the dangers of careerism and incumbency, but I believe that is a direct result of big government intrusion. If we’d stayed within our Constitutional limitations, say going back to the Lochner era, we wouldn’t have the trouble with incumbency. Undoing the 17th Amendment and a return to Federalism would get rid of a lot of career politicians and return the Senate to its patrician and pro-state role.