The problem is that when a company owns the last mile it has a natural monopoly. An incumbent being overthrown isn't the same as having long lasting competition.
Provo actually already has a fairly significant fiber rollout from multiple failed local and municipal coalitions to bring 100Mbps+ residential connections to the area. I believe these lines are owned by the city, and that Google plans on utilizing the extant network as far as possible. It is pretty likely that this won't be the typical municipal telecom monopoly that we've seen to attract cable providers and the like.
Also, they bought out a municipal fiber outfit. They're not kicking competitors out. They're just completely outclassing them.