Odds of Hanging On
If you do your job well, there's no reason you shouldn't have a long and happy career as a corporate events manager. Be the best events manager you can be, and you might survive a Wolf of Wall Street-style hostile corporate takeover or two.
While the above is in your control, there are other factors in your job that you don't have any say over—namely, the economy. The reality is that when the economy suffers or when a corporation's numbers aren't where they would like them to be, things like conventions, parties, and meetings are often the first to get slashed from the budget.
No events mean no events manager, which means it's back to the world of catering and weddings.