This seems like a straw-man argument. I'm simply recommending that doing something that increases density and reduces commute time and sprawl
while also accounting for environmental factors is strictly better than doing nothing and waiting for people to just stop moving toward the Bay Area.
Rehabilitation of wetlands is a very important goal in itself. Now that 99% is already gone and fucked up (virtually beyond repair) ... well, it means it's almost irrelevant what happens to the remaining 1% if the other 99% will be "restored" somewhere else, then that 1% can be "moved" too.
Not to mention that it the fugly plain of endless mansions sitting where the wetlands were would be replaced with a few high rises, there would be ample space to recultivate a big chunk of it.