If they were already testing on a "massive scale" and we, a forum with 1000s of members and TDU2.com with the same numbers hadn't had one person selected I don't see how that would work, and even if it was being tested by loads of people, word would have got out anyway.
A delay is possible, I wouldn't want it from some points of views but from other points of view I would.
Who knows? They could just be planning on a very small time scale for a Beta test. As in a week or two, not a whole month or something like that. Maybe they're confident enough that there shouldn't be that many bugs to find so a short Beta test is all that is needed or something along those lines.
At the end of the day, all you can do is wait and be patient. It's been said time and time again. Speculating it and talking about it wont make the Beta come along any faster. If there is going to be one Atari will release it as and when they see fit.