Thanks for your comment - I'll do my best to answer your questions.
1) NFC does require you to activate "something" on your phone. On some devices it's a specific key, on others it's an app. There's two reasons you don't want NFC continually running - battery drainage and your phone buzzing every time you're near an NFC tag.
Regarding the number of QR readers. A cursory glance at the major app stores show that they are heavily downloaded. The number of shipping NFC phones is close to zero.
2) Yes, I am. Clicking on my QR reader icon is a quick as clicking on my SMS compose icon. Scanning in a code is (usually) sub-second. I would say they are of comparable speed.
Here's a video I created to demonstrate it
I agree that people are used to SMS promos - but they weren't always. I think QR is lifting off in the same way SMS did in the late 1990s.
3) Regarding volume and stats. In 2009 I blogged about Pepsi's QR campaign
They said the codes generated...
Over 12 million views of their “viral” videos, and hits to their site exceeding any previous promotion.
See some of my more recent posts for more statistics.
I'm not saying that SMS is dead or dying - I think it's a great service. But I do think that QR codes are a great way of accessing information - and whether that comes through via SMS, email, or WWW doesn't matter.
I'm saying that QR is poised to take over as the standard CTA. It isn't there yet - but I think it's wise to take notice of it now.