702
Fingies
(mander.xyz)
A place for majestic STEMLORD peacocking, as well as memes about the realities of working in a lab.

Rules
Tl:dr = Because they haven't. Yet. Maybe. As far as we know.
I think you've described it quite well. That's just evolutionary biology. Any adaptation requires some kind of pressure behind it.
Not pressure, just absence of negative effects. Pressure might help but is not required. And I use "absence" quite loosey-goosey.
Yes, and 'pressure' is used similarly. Think atmospheric pressure. It can lower and heighten, so a lack of pressure is low pressure, not the absence of it.