Why does everything fall apart when I'm gone?
Because the company has never been allowed to make a decision without you.
You did not train them to wait.
You trained them to need your sign-off, and the team did exactly what you asked of them.
The business is not weak. The business is well-trained to wait for you.
What you actually built
You built a company where decisions route through one desk. That is not failure. That is design. The fix is design too.