Why are all wireless router companies locking their routers by default now?

like what’s the point of having an Internet wifi capable phone if there’s never any open wifi around. I mean if the router companies just gave them default random usernames and passwords then you wouldn’t have to worry too much….unless someone uses your access point to download kiddie porn or something, still bugs me. I liked a few years ago when everyone were getting into wireless and had them open….those were the days