In 2012, we have at least 12 so far (in alpha order):
Zac Brown Band
.. and that's not counting Reba, George Strait and a few others who were filling arenas just a year or so ago.
So, the question for me isn't "do we have enough new names who can sell 10,000 tickets on the strength of their own brand power and drive the marketing of country's new generation of music to the new generation of new listeners", but can we possibly find room for any more right now?
No matter how many new artists come through the funnel, we can still only play 14 or 15 songs an hour unless everyone starts releasing 2:30 hits, which would be extremely nice, but shows no signs of happening.