That should be the default assumption, unless you can prove that our current approaches are on the right track... Which I don't think anyone actually believes.
Any strong declarative statements require justification, period, whether that is an assertion of existence or non-existence.
> unless you can prove that our current approaches are on the right track
How anyone can look at the progress in machine learning in audio, video and written expression, and not think "we're on the right track" is honestly beyond me. You can start here:
You literally have no way to make that determination.