Why don't we have to retake driving test/written exam to renew driver's license?

If driving is really a privilege, and there are tons of vehicle deaths every year, wouldn't it make sense to prove someone really understands the correct way to drive before giving them a license to keep driving for another 7 years? Like having to retake the written and driving test seems like it would guarantee that people are generally better drivers than just a fee and an eye exam? What's stopping us from making this change that would, in my eyes, save a lot of lives every year?