Its night and day, though.
Right now it's only analog, or only digital.
Come September, there's no choice. You must be on digital (rural exceptions aside).
Once we're digital, they can maintain legacy MPEG2 for 20 years if they so wish. Can't do that now with NTSC, at least not without using double the spectrum.
It's not a required flash cut, by any means.
I'm not suggesting it would happen overnight, or even in 5 years. But the fact remains that switch would be relatively painless, compared to the one to come.
Especially considering the people will come out from under their rocks and learn about ATSC once their analogs go dark.
Those same people would pay attention the next time they say 'transition in 5 years'
Considering how the cost of technology is dropping, by the time they switch to MPEG4, I doubt anyone would notice any significant cost.
Especially since most people these days have a display capable of 1080p decoding/display. That costs more than the actual ATSC chipset.
And let's be realistic here: What's the last electronic device you've bought that has lasted even 10 years?
I think consumers are going to need replacing or repair of their current gen ATSC equipment long before we switch to next gen permanently.