You've said, jokingly, what is actually the truth!
IF bars are allowed to open until 4AM, they're not being forced to do so. It just gives the owners / managers an option which they can asses using market forces.
IE, if you're the only bar for streets around and are getting (enough) customers wanting to stay until 4, stay open. If, however you're the only bar for streets around and are NOT getting customers wanting to stay until 4, then close.
It's really not too difficult!