It's a commercial subscription. The fact is, any residential ISP is selling the same connection to the internet to 20-100 subscribers. This is known as the oversale ratio. Since nobody is using the whole connection continuously, people experience the advertised speeds most of the time.

The backhaul connections that ISPs resell (and that are sold into Althea networks) are usually around 10x the price of a residential connection with the same advertised speed.

It's the difference between "it is technically possible for this connection to attain this bandwidth" and "you are guaranteed this bandwidth at all times"