Some dogs need less than that, some more. Depends on things like breed, character, age of dog. Taking a young puppy or elderly dog out for an hour could be damaging.
I do agree that there’s a problem with people buying unsuitable dogs, based on their Instagrammability, and then not exercising them enough.
My dog (mongrel, lazy, middle-aged) gets walked 3x per day. Once first thing in the morning and once last thing at night - end of road for a wee, 2-3 mins. One main walk after breakfast. He decides how much he wants for that one - sometimes it’s five mins, sometimes the best part of two hours. He’s not fat, and spends much of the rest of the day asleep. We’d walk him more if he wanted it, but I can assure you he doesn’t 😁