If you haven't seen dogs approaching people they don't know, I can guarantee it's not because it doesn't happen much, it's probably that you've just never seen it or noticed it.
There is a breed of dog owner now that @LakotaWolf mentioned, who thrive on using their dog to get attention, they think their dog is the best dog that has ever existed and they think other people will love them too if they are just given a chance.. so they don't bother training it or keeping it under control and they let it approach adults, children, other dogs etc.. usually with a shout of 'don't worry, he's friendly'! In fairness, normally they are friendly enough, but they have no manners as they have never been taught, and if they end up in a negative interaction because children/adults are scared or other dogs may be reactive, the owner will refuse to see it as their fault.. they're thick as shit basically, and shouldn't own a dog IMO.
I've had dogs all my life, total dog person, and lockdown was where everything changed for me, my dog now, who minds his own business, was chased, jumped on, mounted, and confronted by so many of the above dogs with their stupid 'they're friendly' owners, that he won't tolerate strange dogs coming near him anymore, and even though he walks next to me off lead usually, I have him on lead when we pass anyone, just to reinforce the message that we don't want to be approached.. 90% of dog owners understand that unwritten rule, but we STILL we get approached by ill mannered dogs with idiot owners who want to force an interaction.