Good ol George Washington warned us about political parties but alas we failed him there....
I will say at least in the House of Reps side yes there are some career politicians but there are also a ton of people who are not. On my Committee we have several ranchers, a guy who was a weatherman, a dentist, a guy who has a PhD in I believe Plasma Physics (he worked for the national labs), numerous small business owners heck even a guy who helped build the freaking Saturn Rockets for Apollo (he is retiring).
The Senate side tends to be career politicians in my opinion because they are people who have climbed the latter from things like Congressional or State Office. If they arent then they tend to be very wealthy people who may or may not be in touch with the Common Man anymore but again because that is the chamber that only has 100 people and is thus much more powerful per person wise compared to the House I see how it could easily happen.