Absolutely. First, with decreasing budgets for staff, politicians need to be full time in order to review everything that they'll be voting for. Second, you need politicians to be invested in their position, and ambitious with their political goals [[that is, they have to be invested enough that they'd care if they weren't reelected for going against the will of their constituents). And then in addition to those things, the government is complex and we need politicians with the institutional knowledge to get things done.

The political class is only as permanent as their performance justifies. If a politician doesn't adequately represent the will of their constituents, or a more representative candidate comes along, they will lose their job. It shouldn't be much surprise that the same geographic area with the same demographics is remains satisfied by the same politician.