Any single person's declaration that something is scientifically plausible or implausible is either invoking broad scientific consensus, or else is reflecting the sole opinion of the speaker.
You are flatly wrong. The
plausibility of a structure of assumptions compatible with the empirical evidence is determined by its complexity. The
plausibility of a single proposition is that of the most plausible structure in which it can participate.
Kepler's model of the solar system didn't become plausible because men with credentials embraced it; fortunately, men with credentials eventually embraced it because of its already established plausibility.
We have peer review and journals and conferences and so on and so forth for a reason.
Peer review in scientific journals does not test work for conformance to a consensus. Peer review in scientific journals has, for each paper, a tiny set of experts ostensibly pore over the evidence and argumentation looking for weaknesses.
Unlike you, I've had work
pass peer review in respected journals of science and of philosophy, in the latter case, producing foundational work on
the formal logic of plausibility.
I understand that you, as a non-scientist, aren't well positioned to do a lot more than to use consensus as a
proxy for plausibility; but you shouldn't dive into debate about the plausibility of propositions where you've only got that rather poor proxy.
Even with them, we have great difficulties overcoming the various biases and selective blindness that any particular individual has.
And that problem is actively
worsened when the bias of the individual is to the adoption of an orthodoxy, as when the
opinions of many are mistaken as objective and unbiased simply for being wide-spread.