People abusing party in progress option

[Frein]

right, because SE told people "hey guyz, withdraw when you can so we give you a prize"

Yes, that's actually exactly what they told them. By withdrawing until you get a nearly completed run, you save time. They're REWARDING this type of behaviour, hence there are poor incentives built into the system.

A car manufacturer does not reward its clients for crashing their cars. When you drive over someone, you may damage your car and in general get into all kinds of nasty legal trouble. You're hardly incentivized to drive over someone. This is why your comparison was utterly moronic.