When you want to compete in the marketplace you don't get to re-do your competitors time-frame when they rolled out. You get to play by the rules of today.

So whether it took Facebook an hour, a decade or 2.5 years to roll out their API, right now they've got one and right now google is trying to compete with Facebook through their g+ offering.

Why not? Why are they rushed? They're trying to displace a competitor who was first to market. It's not going to work the same way, so quickly rushing out to make an API isn't an automatic assumption to be made relating to if it will help you be successful. Keeping higher quality content in G+ seems to be their current goal - whether that means there's currently less content overall initially, I imagine they're quite aware of their overall analytics.