Is The Truman Show's ending the best series finale ever? + Theory

Think about it: it was what the audience wanted, it was thrilling but with an ultimately happy (at least it seemed happy) ending and probably the audience didn't want to see him old or dying.
It looks like clever marketing, indeed.
So i have this theory:
Was it all planned?
Was it all a plan by Chrisof to make The Truman Show end in the best way?
Christof probably worked a lot, probably didn't slept very much he watched monitors for quite a long time per day, he clearly had an obsession, maybe he developed some kind of illness and he was afraid to die and lose control of The Truman Show before the it ended.
I think it's a good theory but again, it's just a theory.