A graphic posted to a Chinese website (via MacRumors) claims to contain information about Intel's forthcoming third-generation Thunderbolt controller, code-named "Alpine Ridge." The slide claims that Thunderbolt 3 will double the bandwidth of the current Thunderbolt 2 – announced in April 2013 – from 20 to 40Gbps.
The real question: are Intel and Apple beating a dead horse?
Why do Intel and Apple keep advancing a technology that few people seem to use? Mostly because it's backwards compatible with DisplayPort, so it's not really hurting anything or "stealing a port" and because pros that need it, really appreciate it. If you're transferring high resolution video files (like 1080p and 4K) and your business is deadline-based, Thunderbolt is a huge deal and there's no such thing as "fast enough."
I've only ever plugged a garden variety (Thunderbolt 1) display into my Retina MacBook Pro. Even though my Mac supports Thunderbolt 2 there's a dearth of Thunderbolt 2-capable hardware on the market save a few SANs, card cages and expansion boxes. Luckily Thunderbolt 2 is backwards compatible with the first Thunderbolt 1 and DisplayPort and doesn't require an adapter.
According to the leaked graphic, Thunderbolt 3 will support PCIe generation-3, charging up to 100 watts, and have its power consumption reduced by 50 percent. Thunderbolt 3 will be also backwards compatible with Thunderbolt 2 and 1 (and presumably DisplayPort, too) but it'll require an adapter as the new TB3 port will be physically smaller than the current one.
Although USB 3.1 just hit 10Gbps it only just caught up with Thunderbolt 1 (and is half the speed of the current Thunderbolt 2).
As I noted in my piece about Thunderbolt Networking, USB 3.0 is currently capable of pushing 5Gbps while Thunderbolt 2 is capable of 20Gbps and Thunderbolt 3 will double that to an impressive 40Gbps. Pros that need to push a lot of pixels across the pipe will love the increase in bandwidth, everyone else will continue to use USB.
What do you use Thunderbolt for?