Onlive, now Cloudlift, is planning to offer a similar service at $14.99 a month. Currrently $7.95 a month for the open beta. https://games.onlive.com/games#selectCloudlift
The catch, you have to buy the game first. It streams your Steam library games (50 for now).
$7 for a week per game is pretty good. The problem with a monthly subscription is account sharing and heavy users driving up the costs. Some limit should be in place. Maybe a prepaid model, buy game time per hour, or a tiered subscription model with different usage allowance, $50 a month for unlimited gaming.







