The first question's answer is, "it depends". If you're "well-qualified", you can get a rate that most people would consider pretty reasonable, particularly in the new car market. If you're not well-qualified, well, a high interest rate and a long term (think 5-7 years) are waiting for you.
Second question's answer: No. They're not. 40 years ago the powers-that-be in the American financial system decided it'd be a great thing for their balance sheets if everything was turned into a purchase on credit, and for purchases that were already on credit (homes, cars, business capital, student loans) to draw even more in the way of fees. Meanwhile, everything's become more expensive (as it can be on credit) and wages have remained stagnant.
In the off chance that they are able to save for retirement, tax law makes it something you don't want to draw from until you're retirement age. If you have a 401k, for example, and withdrew from it to purchase a car, you're going to be expected to pay the tax on the money you put into it immediately.