Imagine if a regular for profit startup did that. It gets 60 million in initial funding, and later their valuation goes up to 100 billion. Of course they can't just give the 60 million back.
This is different and has a lot of complications that are basically things we've never seen before, but still, just giving the 60 million back doesn't make any sense at all. They would've never achieved what they've achieved without his 60 million.