Nvidia SHIELD console may not be a huge success in sales for various reasons (such as the decline of the console market), but it has been received pretty well by users because it's a quality product. SHIELD promises to let you play Android games, PC games through Wi-Fi connection, and now games powered by the cloud, too (much like the OnLive idea). Some users are already starting to receive this GRID Beta update for cloud gaming, today.
To make it work reasonably well, there are some requirements such as having an Internet connection of at least 10 Mbps, home network with 40 ms or less ping time to the GRID cloud gaming servers in San Jose, CA, and an Nvidia GameStream-ready 5 Ghz router. The beta is limited to the San Jose area for now, but if other users have a fast enough connection with that kind of low ping (such as Google Fiber users, for example), then it should work for them, too.
Cloud gaming, if available to all, could make the SHIELD a lot more interesting to potential customers, because it can allow them to play games that even their PC can't play at high enough settings. But such a future always seems 5 years away, especially with the poor Internet connectivity in US, and until most people get gigabit connections, cloud gaming will always have its issues, at least for some users, if not for all, which can be a deal-breaker, compared to playing local games.
Nvidia's SHIELD console could still end up popular if the next-gen one comes with PC-like Kepler graphics on its own, and costs only $199, which I believe is the pricing sweet spot for such a console. At that price, and that level of performance, Nvidia could move millions of units per year, which would be quite decent income for a company like Nvidia.
Even better, it would provide an excellent launching platform for Tegra 5 and future Tegra chips, because Tegra could become an established mobile chip brand for mobile gaming. Nvidia just needs to make sure there aren't anymore delays next year, and that their chip is inexpensive enough for OEM's, and also efficient enough in power consumption, so it can be used in smartphones, too (which is really the market where they can sell the most chips).