That's a dumb example, there's no life in those environments.
You could look to the intertidal regions near the equator for more reasonable comparison. They are much less rich in life compared to the waters around Vancouver.
Ah, that final newly added sentence turns your post into something that finally makes any sense at all and no longer contradicts GP’s point that I am arguing.
The point others and I are making is that life does not expand arbitrarily, or in a weaker form, the life that may expand will be a much less desirable environment for us humans than the present.
Even though you deny it, we can very simply create environments, right here on earth, where life as we know it will not be possible. Look into an operating steel smelter for example, just to remove any subtlety and ambiguity.
Sure, maybe ‘Science’ can replace all of our biosphere with extremophiles, but I for one do not desire to live in such a world. I like trees and birds and mammals and lizards and (you get the point).
You could look to the intertidal regions near the equator for more reasonable comparison. They are much less rich in life compared to the waters around Vancouver.