hmm, something is weird there. It doesn't say how often the 600k hit their site, but presumably that's per month ("We have hundreds of thousands of hits per month"). Google Maps allows 25k map loads per day for free, which is already 750k for a 30 day month.
Even if you allow for overages that would cost money, it still doesn't add up. If you double that to 1.2 million per month, that's $12.50 a day, or $375 a month, which is still under the $499 a month Mapbox "Premium" Plan (which only gets you 1 million loads per month).
And that's not even touching enterprise pricing, which presumably has a discount for volume (it's really dumb that gogole doesn't publish those enterprise prices though).
I think Google's enterprise pricing was targeted towards, say, a long-haul trucking company or a corporate GIS department where the viewers are just some managerial or analyst staff. In cases like that, if they charged the same rates as they did for CraigsPinSquare, they'd make a few pennies. Thus, the solution would be to discriminate pricing between high-volume consumer-facing usage and low-volume internal "enterprise" usage, especially since internal "enterprise" usage wouldn't give Google Maps much publicity.
Google decided that we fell in the "enterprise" bucket, and enterprise sales typically involves private negotiations with pricing. It's very possible that we got wildly different pricing than other companies.
We're still open to using Google products in general, but OSM is more fun.
I've been involved in negotiations with Google for their mapping service. I can't give specifics, but will say we settled on another commercial service that was two orders of magnitude cheaper for our use case.
(In our case OSM wasn't a viable option, as mapping data in my country is very poor).