Ugh, the ISP will not being limiting bandwidth. The connections themselves will take care of that. It's called QoS (Quality of Service), and it means packets from certain address have pipe priority.
Companies that buy the "fast lane" (God damn do I hate that term) will be placed higher in QoS. Everyone else will just have to wait their turn. If that means a site that didn't sign up for QoS has to wait so long for bandwidth that their users literally time out to connect....tough shit!
The other downside being is if too many people buy QoS, it doesn't work. It has to be limited, meaning it'll be priced outside of the reach of anyone but the wealthiest of businesses.
It's much, much worse than you're making it out to be