Broadband speed tiers, especially in the modern fiber era is a borderline scam.
Just set everyone to the link speed of the underlying transport and be done with it*. It literally costs us more to manage and sell higher speed tiers. Some ISPs really should be thinking about how much those salespeople are bringing in borderline scamming people, taking into account their pay and also all the systems and stuff needed to manage it. Dropping all that complexity and you may not even need a "Broadband Network Gateway" (a hugely expensive piece of gear that ALSO limits an ISPs network scalability by beeing a choke point BTW)
Most people wont even use more in total and even if a few customers end up maxing out their connection 24/7 the extra bandwidth is just a rounding error for an ISP anyway.
* Of course there is *SOME* nuance to this when there is shared last mile like coax/HFC and to some small extent GPON