They're limiting the number of CPEs per cell to a maximum number of sites, and volume of traffic, such that the service won't degrade to a viasat/hughesnet like terrible consumer experience. I can't say how I know, but some very experienced and talented network engineers are designing the network topology and oversubscription/contention ratio based out of their Redmond, WA offices.
In rural areas, contention should stay low enough that the speeds will continue to be at least decent. And of course the latency is much lower than geosynchronous satellites, independent of bandwidth.
Family in Placerville CA went from unusable <1mbps viasat to 50-190mbps overnight.
I hope it puts all the geostationary satellite companies into bankruptcy.