I visited a dozen+ countries in 4 continents last year - GMaps did a pretty decent (often great) job with public transit. In the cases where there was no/bad data, it usually had more to do with the transit authorities being jackasses than anything in Google's control (Melbourne in particular stuck out as being just terrible).
Well, that doesn't solve the question with the cities where here.com and bing maps have full transit data, and where the data is available via simple REST APIs, but where Google still doesn't have data.
BTW, the Android-App "Öffi" has full support for Melbourne, as Melbourne provides a simple to use API, and has for the past years.
I was involved in a lot of (too many) geo/transit/open data conversations in the late 2000s, and sadly, this kind of short-sighted/nonsensical thinking was all too common, and I'm sure persists in many of the places where people lay the blame on GMaps, when it's actually due to stonewalling bureaucrats.
So don't extrapolate your city to the rest of the world.