Not to be pessimistic, but don't overestimate your leverage. You may know that you leaving would be a big setback, but the founder may not. Careful with the ultimatum approach too. Even if the founder gives in, it may create resentment if your conversation ends up being "if you don't do this, I'll leave, and everybody else will follow!"
It's interesting that you think that a very small company is more likely to implement this new policy. I would have said that a bigger, more stable company would be a better candidate. Founders at small companies are betting everything on their shares, they will be more reluctant to giving them away too easily.
Not to be pessimistic, but don't overestimate your leverage. You may know that you leaving would be a big setback, but the founder may not. Careful with the ultimatum approach too. Even if the founder gives in, it may create resentment if your conversation ends up being "if you don't do this, I'll leave, and everybody else will follow!"
It's interesting that you think that a very small company is more likely to implement this new policy. I would have said that a bigger, more stable company would be a better candidate. Founders at small companies are betting everything on their shares, they will be more reluctant to giving them away too easily.