I just take it to mean that the reboot is set in a time period (the 2090s, I assume from what we know so far) when anything they do won't really impact on the old stuff very much. After all, that is about a century before the xenomorph infestation of Earth, which is really the point at which they would have to start seriously taking the old EU into consideration.
As far as the multiverse, I wouldn't discard it; there are still plenty of stories in the EU that will benefit. Anything involving the old Dark Horse interpretation of the Jockeys is a good example.