The issue is mostly that it’s highly variable, hard to change without moving, and hard to predict before you actually live somewhere.
The comcast rep will happily take your money to put you on a 200mb plan, but it won’t do shit if the infrastructure in your area is bad, and Comcast (or whoever the isp is) has absolutely zero responsibility to actually provide the promised services. Now you add in that 95% of the population including most of the phone reps working for the ISPs don’t even know the difference between a bit and a byte and it becomes a total crap shoot.