The hourly rate example is a clear tell. If you're selling your time by the hour you're already doing the wrong work. Consulting = death, and I mean that literally. The months of our career are finite and we should allocate them carefully
Consulting with value—based fees is a fantastic way to deliberately allocate our finite time .
You can only get the value of your work over time though equity. If your impact really is large, nobody could afford to pay the net present value up front (and only a lowlife would want to damage the company by taking out cash like that)
Equity increasing in value, as has been discussed on HN multiple times, is not a guarantee - and businesses engage all kinds of other businesses for all kinds of help.
There are lots of ways to structure a temporary engagement that's mutually beneficial to both parties - in the short & long term.