Well, companies do offer isochrone APIs. That, or graphical maps, are Produced Works under ODbL and only need attribution. Actually enabling that was the point of licence switch in the fall of 2012 which while mostly successful wasn't without pain points (e.g. in Australia key contributors rejected new Contributor Terms and their edits had to be redacted).
It says clearly there that the underlying database for a produced work has to be published. So can a competitor not just request the derived database directly from a company selling the API?
Also, “ If the published result of your project is intended for the extraction of the original data, then it is a database and not a Produced Work” - does that not exactly describe an API? It talks about mugs, data visualisations, map images, physical maps and so on as produced works. I thought this meant you could protect (i.e. not release) essentially a styling of map data, but not the map data itself, which must be released.
