In that example the goods stolen are tangible and have real, solid value that anybody can recognize.

In the case of things covered by GDPR the value is opaque and intangible, and only valuable to certain people. Letting 'the free hand of the market, driven by the layman who doesn't understand this, is not effective.

If you want proof, well, it's in the pudding.

Edit: also, if banks wheew getting knocked over as much as sites and apps, the government would intervene

I have yet to see a person against regulation that didn't run screaming for the authorities as soon as they were tricked, swindled, defrauded, abused by some company because no regulation was put in place.

Most recent cases that come to mind are Bitcoin thefts. "The government shouldn't do anything to regulate or even look in the general direction of Bitcoin". Oh, the exchange left your pockets empty? "The Police and the government should do something!"

Companies aren't scared of consumers because as a mass they have no idea what's good for them or how to protect themselves. Without a watchdog we'd all just be open for abuse with no leverage to stop it. Companies are far more motivated and capable to abuse you than you are to defend yourself.

It's not the same situation because in the case of a bank the risk is obvious to anyone, but it's might be hard for non-tech users of a chat app to understand the dangers of unencrypted passwords. It's the same like regulating the other industries, say layman can't assess how good lawyer or civil engineer someone is, so government requires them to have certain education and licenses or they can't work. We will need something like that sooner or later in IT because there's simply too much amateurism in industry now, where everyone and their mother has a startup these days and people with no proper experience and knowledge are trying to handle often very sensitive things. Just look at crypto-market and all those hacked sites - not hacked because hackers are evil geniuses, but because programmers who built them suck at their job... and market can't regulate it itself because the demand is so damn high