I don't think so, because HBO's old content is already widely available. It's only kind of good for retention, and that only on HBO Go (and Amazon, now that it's there too).
The competition for new subscriptions and paying that one more month always takes place in the present/future, or at least for content you haven't watched yet which for any fan is going to be present/future.
And Netflix is kicking ass there, TBH. They have high-quality dramas, resurrected cult (and my!) favorites, the deal with Marvel, and probably half a dozen other things that got me salivating that I'm forgetting.
To be honest, I think Netflix, Amazon and Hulu are -all- schooling the old school providers in terms of interesting new content, HBO included. I love Six Feet Under, Mr. Show, and Deadwood as much as anyone, but aside from Silicon Valley and GoT, nothing else current excites me. At the very least, HBO needs to get much better at both making -and- fulfilling promises.