And I agree, though I don't think Google did it on purpose. Their main aim---I think---was just to avoid Apple (or Blackberry) becoming too powerful. They wanted to commoditise the smartphone market. And they have succeeded.
And to me it doesn't look like the hardware manufacturers got a great deal either. It's turning into a cut-throat market, where all phones are pretty much identical (and interchangeable), and your revenues come from economy of scale. Basically like the PC market.
Normally (e.g PC market) this would mean that the customer can shop for the best deal, which is great. However the "customer" here are the carriers: they buy from the manufacturers and resell to the real customer. And indeed they got all the power: they can ask this or that company to lock or modify the phone under threat of taking their business elsewhere.
The real customer, however, is only dealing with the carriers, and Google hasn't commoditise these. If anything we are getting even more market concentration.
So yeah, it seems to me to be pretty much what economics theory would suggest.
The only alternative would to get an unlocked phone but then the manufacturer would lose the massive subsidise and most users seem to prefer those to the hassle of getting a closed system from their carriers.