When we talked about "2000", we were (generally) referring to the "end of the 2nd millennium" and correctly it ended at the end of 2000. But we are NEVER going to fix this in the minds of people, especially ten years later (and Integral, when my kids were born, it took a whole year before we said they were "1." This perception dominates all other considerations, and is what makes the correction nearly impossible. We have to let it go!)
However,
When referring to decades, we are ONLY referring to how they are spoken. The "80s" were a ten year span in which the date included saying "eighty-___." This included 1980 itself. This past year, everyone said "two-thousand-four" or "two thousand and five" and such.
I predicted people would be saying "twenty-O-four" and "twenty-O-eight."
Nope.
But I do think that in a few decades, we will be saying the years as "twenty-thirteen" and "Twenty-twenty-five" etc. By that time, I am certain we will retro-activley refer to this ten year span in the manner of "twenty-O-seven" etc. Thus, I'm sticking with "Twenty-Os."
Give it time.