Giving characters a standard Wealth Rank of 4 means that unless modified downward by a Burden, Characters can theoretically purchase things all the way up to Rank 7 through Debts and Long Term Goals. But we've been asked a couple of times about Wealth Rank 8 and how Characters can increase their Wealth Rank, as the Financial Gift only lowers the Success Number needed for Wealth Checks.
The answer is, we intentionally didn't create those rules. You're welcome to add them in. Based on the current rules set, it wouldn't be hard to imagine how to do that. But it's not part of what we're concerned with in our core game. If the idea of getting rich, owning corporations, buying industrial gats, own fleets of sunwings, etc., is your thing - cool! You do you.
But we think you'd find a Character with a Wealth Rank of 8 -or even a 6- to be rather boring. If wealth accumulation is your thing, consider how that might effect the people around your character and what that would look like in this world.