that was done because when wifi encryption wasn't enabled by default, most people had no clue how to turn it on. so now it's the norm to enable encryption and supply the default credentials (which you should still change) to connect. this is why there's hardly any 'open' wifi to 'borrow' anymore.
At least now the default settings on most routers include a unique WiFi password printed on the router, so either that password, physical access to the router, or a serious security vulnerability in software that never receives updates (gee, this list is getting long) is necessary to compromise the router.