A lot of these people have also probably been doing it since they were kids/college students-- they were either using their parent's or a roommate's account, and couldn't really afford their own. They're now in their 20s and 30s, and can (maybe) actually afford the bill. They never switched before this because why would you, but now that they can both afford their treats and are forced to get their own accounts, they're doing so.
A lot of these people have also probably been doing it since they were kids/college students-- they were either using their parent's or a roommate's account, and couldn't really afford their own. They're now in their 20s and 30s, and can (maybe) actually afford the bill. They never switched before this because why would you, but now that they can both afford their treats and are forced to get their own accounts, they're doing so.