Is there no invention related to car password, i.e using password to unlock a car instead of keys?

Stealing physical keys is risky small scale business, hacking perhaps not

Consider having to make this choice: Walk up to someone, put your hand in his pocket, grab his key, immediately get into his car, drive away, sell it for whatever you can get Hack something, arrange a sale (passwords/actual car), at a convenient time (let someone) pick up the car for which you know you can get good money Considerations

Even assuming that looking at the car password as they enter it would not be possible, it is going to be much easier to steal a car and get away with it. So, perhaps the number of keys stolen in bars will decrease, but the number of passwords stolen should easily make up for that. Addressing other points that are mentioned in the question

Car keys can get easily lost or stolen by a stranger you met in some pub but it's highly unlikely that you shout your password while you are sleep talking

Your classical key can only be stolen by someone who has physical access to it. So, anyone who attempts to steal a key will have to take a considerable risk and consider the possibility of being in jail the next day. Also, the person will not only need to steal the key, he needs to use it immediately to get in the car as the opportunity will otherwise have passed. Someone who has stolen your password code can probably remain anonymous, only facing some risk when he finally picks up the car at a convenient time. After all, you will not know that someone else has your password now.

It's a big hassle and an expensive process to change your car keys; Passwords are very easy to change. As it cannot be acceptable that people can't use their own cars, the keys probably need to be stored somewhere centrally. Also digital keys tend to require changing much more often than physical keys as it turns out people are better at stealing them. Therefore, the annual revenue generated by 'administration costs' will likely be much higher than the total spend on key replacements at the moment. You can always use your car as a getaway car in a bank robbery and you later claim that you have lost the keys and it was not you; you can't do that with a password. I don't see why people couldn't claim that someone has stolen their password.