I hope that's not case ... I just bought a license. The blog post says:
All license keys purchased since the previous blog post announcing Sublime Text 3 are already full Sublime Text 3 license keys, and no upgrade will be required for these purchases. Please note that while these are Sublime Text 3 license keys, they are also valid for Sublime Text 2.
The previous blog post was made on January 29, 2013 2:47 pm. So, it's my understanding we can use ST2 and ST3 beta and ST3 when it comes out without any upgrade.