Exactly, there simply isn't any consumer demand for higher speed peripheral connections. SSDs have just barely started to exceed SATA II speeds, but SATA III and USB 3.0 offer plenty of headroom for that already and at least for a couple of years, using cheap, backwards compatible hardware and connections. Besides that, wireless peripherals are on fire - its the only kind of kb and mouse Apple ships with their iMacs - even Time Capsule, which handles multiple backups of entire systems,is wireless.
I don't really understand why anyone would want to invest in new, expensive hardware for higher speeds and leapfrog proven, legacy-compatible alternatives which have over a year on the market and already supported and matured?
If Apple delivers MacBooks with Lightspeed rather than USB 3.0, they are just going to make users pay ridiculous prices for connectors and cables no one in the PC world uses, like they did to Mac users with Firewire and DisplayPort,and skip the practical, cheap workhorse ports PC users get value from everyday - eSATA, USB 3.0, HDMI, DVI-D.