Sprint is introducing a new service plan today called Unlimited Freedom Premium, which sort of inherently highlights the fact that its last unlimited data plan was not, in fact, unlimited. The new Premium plan isn't unlimited either, but it is much closer: rather than limiting you to low-res 480p video streams, the Premium plan allows unlimited streaming at 1080p. It also bumps music quality streaming from 500 kbps to 1.5 Mbps, and gaming from 2 Mbps up to 8 Mbps.
Apparently there's a lot of confusion around what "unlimited" means
To be clear, that means Sprint will still be throttling subscribers when they're streaming videos, music, and games. But they'll be doing so at somewhat more reasonable limits — cutting you off, for instance, from streaming 4K video. The music streaming cap should be high enough to let you stream lossless audio. Although gamers are still likely to take issue with Sprint's slow 8 Mbps gaming cap.
The Premium plan is perhaps a response to T-Mobile, which offers a very similar option for its unlimited subscribers. Like Sprint, T-Mobile has a baseline unlimited plan that limits video streaming to 480p; it also offers 1080p streaming for customers willing to pay an additional $15 per month. Sprint is charging an extra $20 per month for that privilege, bringing the unlimited plan up to $80 per month for a single line. In both cases, the plans are pretty expensive and still come with limits that could easily make someone prefer a small but restriction-free data bucket over an endless but restricted one.