It's definitely matured enough, and Rovio initially intended to release a paid app alongside the free one.
However, they still haven't, and given that press release from a month or so ago stating they were on track to earn $1m per month from the "free" version, I'm starting to see why they haven't. I doubt they'd make anywhere near as much ongoing ad revenue if they released the game for a dollar or two.
Comments
It's only free because the Android marketplace hasn't yet matured enough for a paid app. To compensate, the Android version has ads.
It's definitely matured enough, and Rovio initially intended to release a paid app alongside the free one.
However, they still haven't, and given that press release from a month or so ago stating they were on track to earn $1m per month from the "free" version, I'm starting to see why they haven't. I doubt they'd make anywhere near as much ongoing ad revenue if they released the game for a dollar or two.