Hippies didn't have the internet. Some had some of the right ideas, but it wasn't easy to connect the dots of information or insight people had, so a lot of early ideas of improving the world just had to fail against the onslaught of capitalism. Currently we live in a period where the mainstream system seems to fail. The real dystopia doesn't just happen somewhere else to some unfortunate few, it's quite obviously popping up everywhere in many forms.
Solarpunk steps in and imagines that we could build a future that isn't more dystopian. We could take stock of what we have - technology, skills, limitations - and dare to imagine a future that is actually less dystopian than what happens now. We refuse to accept that this is the best version of humans inhabiting the universe that we could possibly come up with, and collect material, information, documentation to support a worldbuilding effort that aims for a better future.
Have the hippies failed? Or did they point the way towards a lot of the right directions? Is punk dead? Don't think so, and it's all in favour of DIY. So we basically DIY our future here.