I agree with you that technology can be used for good, neutral, or evil purposes. I also agree with you that the largest tech companies are not all good. They are desirable because they pay well, but not to everyone. I left a job at Google, for example. (Ironically... you mentioned health, and I was lucky enough to work on health while I was there).
The weird thing is that we are the tech industry. Almost everyone I know in tech reads Hackernews. If we are cynical about our own industry, it becomes a self fulfilling prophecy.
The idea that no industry can change the world for the better seems overly pessimistic to me. If you take a broader view going back to the 1500s vs. now, it's clear that industry has played a role in making the world better. I expect this long term trend to continue.
There is definitely a growing trend for green technology, I don't see why you think that, for example, Tesla isn't a tech company that will play a role in helping the planet.
There are plenty of problems besides climate change, even though that is a huge one.
As I mentioned in my post before, a lot of the reasons we face these problems is related to the fact that the market does not properly price things. So of course there is going to be a mismatch between work that pays well and work that benefits society. Is this mismatch permanent? I don't think so. Is it uniform to all work? I also don't think so.