Uhmm.....
Peer to peer, no tying up CPU resources
PCI-e devices are not driver-less. There is software running on the CPU.
Speed, two bi-directional data lanes at up to 10 Gbps, for now
The indepenent SuperSpeed ( e.g. what is unique to USB 3.0 over 2.0 ) link is bi-directional. (separate set of wires than the 2.0 data transfer on in the same cable) It isn't 10Gbps but if dealing with 1Gbps devices that isn't an issue.
With electrical connections, 10W of power
Again if devices require 2W of power a non issue.
Limited to 7 devices including host and may have to break chain to insert/remove device. This one cuts both ways. USB ports are typically more prevelent so don't need to chain ( 4 USB ports versus 1-2 TB ports).
Simplicity, one connector for all peripherals and accessories
FUD. A TB Display has all the legacy ports on the back. It doesn't provide a reduction in total system ports. Thunderbolt merely allows those ports to be moved; not reduced.
Except for some limited corner cases, (e.g, where SATA controller is bunlded into drive enclosure), thunderbolt doesn't result n a net reduction in ports.
With optical connections, future speeds of up to 100 Gbps and beyond.
The same core technological improvements that allow Thunderbolt to move forward on speed at more affordable cost are basically also available to Ethernet, infiniband, SATA , and USB. There is nothing unique there.
Thunderbolt's previous live as Lightpeak sinificantly leveraged optical USB 3.0 work that Intel did. Again there is a present distinction but nothing necessarily unique going forward.
Thunderbolt will probably go to 20 Gbps around the same time USB 3.0++ goes to 10 Gbps but that will be several years after Ethernet and Infinband went to 40-100 Gbps. It is a reasonable middle ground between top end and commodization zone.
True, the average consumer probably doesn't need this right now, but the way we use technology evolves constantly,
Not only wired but wireless. There are short range 7Gbps demos last week at CES 2013. No sockets is going to beat "one socket" for some folks and some contexts.
This could have left USB3 in the dust.
Perhaps in an alternative universe where USB didn't already have billions of deployed devices, but not in this one.
Thunderbolt is not a shared (committee) based standard. It doesn't have an installed base of billions. Drives up total system costs by pushing the transceivers into the cables.
Thunderbolt will be good competition for USB 3.0. They overlap enough so that USB can't go to sleep for another 8-10 years (like the gap between 2.0 and 3.0 ). However, they are significantly differently targeted that each can have a productive base to work from.