That's one way OSM can compete with Google, it is available for the low price of attribution. Pokémon players have quite some interest in improving OSM.
OSM can also end up with data for things that Google doesn't find interesting. Google doesn't have the nice walking path/bike trail in a local park that I added to OSM several years ago.
That depends. The OSM licence requirements depends on what you do. If you don't produce a geo database, then there's only an attribution requirement, otherwise you have to attribute and release changes to the data you made, along with any other data that you mixed in.
It's like BSD for some uses, and GPL for others.
When OSM started in 2004 (before Google Maps), the only real place you could get map data was from governments. The idea of everyone walking around with GPSes to make their own map sounds like it'll never work. And yet here we are.
> This isn't a case like Wikipedia where it entered a market that was barely there (e.g. online/software encyclopedias).
The encyclopedia market did exist, for decades, before Wikipedia. I'll bet very few people are buying family encyclopedias now.
Main priority of giant corporations is money, no matter what. They will always support mainstream closed platforms only.