There is only so much spectrum to go around. Even with tight beams, providing high speed to everyone in a densely populated area is much easier to do with fiber than with any radio-based system.
In many regions this will be serious competition to comcast, but in cities traditional ISPs won't go away in the next 30 years.
Cities are gaining a higher proportion of the population over time too. It's clearly the better market.
Everywhere on Earth is going to get a big bandwidth increase, expect for cities (and places not allowed for political reasons). It's an advancement that will continue to help fewer and fewer people.
In many regions this will be serious competition to comcast, but in cities traditional ISPs won't go away in the next 30 years.