At least in OpenAI's case I think they take this thing very seriously (Sam Altman doesn't strike me as evil one bit, quite the opposite in fact https://www.youtube.com/watch?v=DEvbDq6BOVM). In fact most of the tech elites don't seem evil to me, if they only cared about money Zuckerberg and Gates wouldn't have pledged away all their wealth. Some of them are as you describe but I think most of them are actually somewhere in the progressive axis.
So far it hasn't worked out too well...
It's up to us. Indeed easier said than done in the current dysfunctional and polarized politics of ours but we can still do it.
For the philanthropy, I'll just note that these pledges don't involve literally transferring 99% of wealth out of their control. The vast majority of the pledged money goes to a trust the person controls, organizations they have some relation to, or just stay completely in their control for years with only vague non-binding commitments to eventually donate it. In return for this largess they get significant reputational and tax compensation.
As nice as this would be, I think there's roughly 0% chance of it happening. Over the past few millenia humans have doubled productivity per capita a ridiculous number of times. None of those leaps led to an end of status seeking or a transition towards mostly leasure time for the masses.
Instead I expect more of the opposite from these developments. Power will get increasingly concentrated with people who have very little interest in the needs and wants of the plebs.