I've never been given an actionable and effective alternative from the people who are squeamish over these kinds of protests. So I have to ask; if not this, then what? If not now, then when?

Infiltrate the political parties, especially the conservative right-wing ones that right now have disastrous environmental policies. These organisations are currently echo chambers driving a narrative that environmental policies are the enemy. They need to be reformed from within to get the message across that capitalism won't work if there isn't anyone around for the wealthy to sell their shit to. As long as political change is confined to what is seen as the "radical left", it is easy to marginalize the moment.