Playwrights

I can't remember the exact quote but Graham Greene once said, apropos the writing of plays, that certain people had the ability to write convincing sounding dialogue without being necessarilly good playwrights. They could write dialogue but had nothing worth saying - the plays they wrote were without substance.
I once was a reader of plays for the BBC in Cardiff; they'd send me a batch of six plays sent in by hopeful playwrights, I'd read them and write comments on them. I was paid little and, of course, it made life easier for the script editors. Most of the plays were not much good. Then I came across a writer who really knew how to entertain with his snappy, witty dialogue. I wrote a quite long appreciation of the man's work though I felt then that there wasn't much in the play.
The BBC took him up, as they say. They met up with him, helped him along to write something for them - something serious. He did. The play was broadacast but was quite poor. He was trying to write an in depth work but really he had nothing to say.
He doesn't write for the BBC now; he set up his own company and writes solely for it. Also he acts in his productions - yes he produces them to.
He is very, very successful.