I don't think Burton watched any behind the scenes footage or any Interview of JJ ABRAMS speaking about the 09 film or even watched the film with JJ's commentary.
Well, that's just non canon meta-information nobody really cares for and that has just been said to make hardcore fans less butthurt. The old timeline is gone, doesn't matter what someone says off screen. If they wanted to make it clear to everyone, they could have said it within the film itself.
The "old" timeline was even shown in the movie in the mind meld between Spock Prime and Kirk. In the "old" timeline, Spock readies the jellyfish with the red matter to try to save Romulus and the rest of the galaxy from the super-duper nova. He is able to stop the supernova, but not before Romulus is destroyed. Spock Prime and Nero were pulled into the black hole created by the red matter. When Nero emerged first, he was in the "old" timeline, but his presence created the "new" one rather than changing the "old" one. It branched off to create its own unique future.
Back in the "old" timeline, nothing that happened in ST09 happened there. The 25th century is approaching, Riker still captains the Titan, Picard may be an ambassador, Romulus has been destroyed but Vulcan exists, Spock Prime is missing and probably presumed dead, and so is Nero. Vulcan and the rest of the Federation will probably pay tribute to Spock Prime's heroic act of sacrificing himself for the safety of the galaxy.
Now, if you're saying the old timeline is gone as in "because of ST09, any more new Trek will take place in the new universe where it's possible Picard and the others are never even born," then you're just speculating.
As plenty of others have said, there are now actually two Trek universes to play in. The commercial viability of the first one may have played out for now, but that doesn't mean it's gone as in it can never be revisited if the time is ripe and people want to see those characters again.