It's pretty standard practice for competition regulators around the world to think about whether new competitors could enter a market. As it ought to be, since

It's pretty standard practice for competition regulators around the world to think about whether new competitors could enter a market. As it ought to be, since that is a real check on the behaviour of the incumbent. Now this might apply poorly to ISPs where there are all kinds of frictions and potential barriers to entry, so maybe the regulator is getting this one wrong. But the court decided not to wade into an argument that is more about economics than law. We could have laws where there was less regulatory discretion. But they would need to be written differently, and as a society we would have to just accept that they will sometimes throw up absurd results in corner-cases.