I still think that baking the non financial responsibilities into the founding legal documents would go a long way towards preventing those goals from being eroded after the initial founders move on even more so after what you shared as people clearly make the personal decision to prioritize shareholder value above all else then, which is somewhat more disheartening.
This is more cultural than legal (and, as the article points out, he had a lot to do with this shift)
That being said, it is absolutely legal as well as cultural. As a corporate director you can and will be sued if shareholders can show you intentionally made a choice to lower shareholder value even after knowing it would.
To the OP, it was Welch (and others) who popularized the idea of this meaning maximizing "shareholder value", but fiduciary duty existed before then and it is the cultural context that has shifted. It lay terms, many people incorrectly think this means that you have a duty to take actions that will raise the share price. But it's much more nuanced than that.
You can absolutely be successfully sued if it can be shown that you did not act in what you reasonably believed to be the best interests of the corporation, but that is a very different thing. Basically your fiduciary duty is to act in good faith, in the interests of the company (& thereby shareholders).
It is a pretty high bar to demonstrate failure, and most normal things that shareholders might gripe about will fall well short of this, and under "business judgement". There are other checks and balances here, bear in mind that if the board is unhappy enough about the approach they can replace the CEO, etc.
Not given. I’d ask for a source, but I’ll save you the trouble of a fruitless search by not doing so.
Edit: The above is apparently more cultural than legal but I still like the below option.
https://en.wikipedia.org/wiki/Benefit_corporation
Give's me hope as a mode to found a company, the gist is:
"that includes positive impact on society, workers, the community and the environment in addition to profit as its legally defined goals"
My understanding is that in the context of the current startup climate is that it is harder but not impossible to raise money under that type of corp though I haven't seen it myself yet.