While I don't think the investors/advisors were necessarily in on this, you're actually mistaken here.
First of all, an advisor could certainly be making money just by drawing a salary or any other compensation. As did Elizabeth Holmes, actually, who drew a salary of 200k (not very large for a CEO, I believe, but certainly this is a very real compensation she got from the fraud).
As for investors, theoretically speaking, early round investors could've sold their shares to later round investors and cashed out.
Again, I'm speaking hypothetically here - I assume there weren't that many people involved in the fraud, just by virtue of the fact that it was kept alive for many years and it's hard to get many people to keep a secret.
