That could add some cost. However, AFAIK (not an expert), the most popular drones are already designed to be connected to a phone – either directly (for short-range amateur models) or with a controller that you attach your phone to. Those devices could presumably use the phone‘s internet connection, so there would be no added cost, although I guess the phone would go from optional to mandatory(?).
I don’t know what you mean by “risk”. Risk of the base station being hacked over the internet? It’s a possibility, but it doesn’t seem like the end of the world, especially since the base station would only need to make outbound connections to specific servers.
* Drones are only ever as reliable as the internet connection.
* Drones cannot be used outside of locations with internet.
* A small number of centralized servers are given authority over a large number of drones. This is a very real risk.
Also, as with many other drone regulations, this does not apply to lightweight units.
From a quick skim of the unpublished document it seems like a compliant transmitter could be built from hobbyist parts for under $100 and weighing a few ounces. Commercial options should have no trouble beating both of those numbers.
It seems like those with drones at the absolute bottom end of the "registration required" range could be limited by this but as long as your drone could handle having a basic flip phone attached to it you shouldn't have trouble with this.
Definitely some rough edges in this that will hopefully get eviscerated in public comments.
When I fly, the "base station" is the controller in my hands. It has no greater or lesser ability to be internet connected than the bird itself. No phone is involved in the operation of any of my machines.