c) Strava is for fred

Yeh that's what's so great about it!

Messing with the API access is one sure way to bring development to a dead stop. Which means that Strava has that as the deliberate objective. They either want to funnel access to their services through their own website or monetize mobile access (and other clever aps).

It could be a mistake. Strava has a lot of data which is their big asset but functionally Strava isn't all that technically difficult. On the other hand if Strava has enough network effect edge from "first mover" status then they'll come out looking pretty smart.