Most environmentalists want to bring a high standard of living to everybody in a sustainable way. Yes, there are some over on the "voluntary human extinction" end of the spectrum, but you shouldn't tar them all with that brush.
Certainly, that's true of most people who support green policies of various sorts.
But I'm not at all sure it's true of the majority of environmentalist organisations and parties.
I think there is as much of a disconnect between green voters and the desires of green politicians and lobbyists, as there is between the interests of Trump voters and Trump's interests.
It's fairly common to hear green orgs denouncing industrialisation, economic growth, free trade, etc. In New Zealand, the Green Party was in part founded by literal Communists, left adrift and unfunded after the fall of the USSR.
To summarise, I think that most people who think they are supporting what you said - a high standard of living in a sustainable manner - are actually supporting anti-capitalists.
I guess it's just a question of how you label various groups? I wouldn't consider fringe Green Parties or similar organizations to be representative of environmentalism. If I should be using another term, I wouldn't object too much.