I don't think people insist on voting for people with no experience or skills, but they should be skilled in life and business, not in politics. Many polticians made careers of this and became wealthy on a government salary

. That wasn't really the intent of any office by the founders. The reason they stick around so long is because most politicians are bought and paid for by lobbiests. They can't just drop out on their own because they don't know how the person coming after them will vote and they have made promises and become rich from their career in politics. There is also the element of power. Power is a very hard thing to give up.
Nobody, except maybe the president, is becoming wealthy on a government salary. Members of Congress make $174,000 per year and have to maintain two residences. If they're wealthy, then it's because they already had money or because they're making money from other endeavors, such as speaking tours, books, and investing.
Politics isn't something that just anyone can do. A good business manager doesn't necessarily make a good member of Congress. There's really not much overlap in the skillset. Consider what makes one good at business: making money, managing organizations, projects, and employees, and setting out long-term plans. How does any of that translate to government? The government isn't there to make money. Members of Congress only manage a small staff and they usually hire someone else to do that for them. I guess there's some long-term planning involved.
No, I don't want a bunch of wealthy businessmen and businesswomen running the government. We've had enough of that. I want people who know how government works to run the government. People who served as mayors, governors, and senators. People who can build consensus, explain policies to their constituents, deal with emergencies and natural disasters, and who can think about people other than themselves and their own companies.
The government is not a business and cannot be run like one. That would be a disaster.
Dianne Feinstein wasn't perfect, but she was a politician with experience being a politician. She was a city councilor and a mayor before she was elected to the Senate. She'd been through a lot and she knew how things worked. As a result, she got a lot done. I agree that she should have stepped down before the last election, but the people of California didn't seem to have a problem with voting for her again.