I've been researching why my cities public transport isn't available in Google Maps. Turns out that the (mostly public) transport company assumes itself in competition to app vendors such as Google Maps and Citymapper; the bus company "doesn't own the whole experience anymore". So, while they give access to static routes with some delay, real-time data or accurate data is out of reach.

How do companies like Citymapper approach that issue? Do they usually pay fees to the transport companies, or do transport companies in the supported cities all give API access?

A proper app would definitely benefit public transport in my area.

(word has it that my area's transport tariffs are way to complicated to be mapped onto Google's API)

[Edit: to be more concise; the transportation company doesn't want 3rd parties to offer an app. How does Citymapper approach that?]