First off, lemme repost this because it was lost in the fray:
I can see where they're coming from. Sony bends over backwards to give people tremendous values from PS+, yet the vast majority of Playstation owners blithely ignore it or have no idea it even exists. Meanwhile, MS puts in zero effort and rakes it in hand over fist with Live subscriptions.
It's not ideal to force a paywall where one didn't exist before, but in this case I think the decision is entirely justified. Forcing a critical mass of people to pay attention to what PS+ offers is the only real solution that will put MS's feet to the fire on how bad Live's value proposition is and force them into offering more. And the IGC will most certainly draw bigger fish the higher percentage of the install base PS+ can point to having. In the end, it's going to better both services.
Secondly, there are a lot of folks ignoring that PS+ throws significant discounts on
purchasing your content permanently, not just 'renting' licenses through the IGC.
And not just a small handful of arbitrarily-selected old content like Live does; New releases are frequently discounted as well. If you have any interest in PSN games, what you save will more than likely offset the subscription fee and then some.
They're starting to be more aggressive with doing this with digital versions of new retail games, too, and their ability to do this is only going to grow the more leverage PS+ has. If a small yearly subscription fee makes inroads against the "we can't upset retail with our prices for DD games" excuse, then that's a net gain.