You are 100% right. Unfortunately, due to the way wireless spectrum works you have no choice but to oversubscribe available bandwidth in the hopes that not ever

You are 100% right. Unfortunately, due to the way wireless spectrum works you have no choice but to oversubscribe available bandwidth in the hopes that not every user is using their devices at once. While they suck for a consumer, limits on total data transferred allow wireless providers to allow users the ability to use their devices but limit the amount of time they are consuming available bandwidth.