What actually happened was Patrick Stewart was convinced he’d be fired pretty early on.
Gene Rodenberry rather famously didn’t agree that Patrick Stewart was right for the role, and Stewart didn’t get on well with him at first.
Gene and I did not have a close relationship. We had a respectful relationship. Gene had very strongly felt that I was wrong for the role…I am told, and I don’t know the details, but there was a lot of warfare that went on in the producers offices about that.
More than likely what clashed was how different Picard was from Kirk – he wasn’t young, he didn’t have a full head of hair, he wasn’t much of a charmer with the ladies, and he rarely if ever got into fistfights. Compared to Kirk, the Picard character seemed kind of boring. Patrick Stewart, having a strong career at the time, was more worried Gene would replace him with someone more Kirk-like, hence he kept his bags packed for the first six weeks just in case of a surprise announcement he didn’t fit what they were looking for and had to say goodbye.
Patrick Stewart isn’t a complete sci-fi snob. That honour belongs to a few of his buddies of at the Royal Shakespeare Company who pleaded with him, “Please don’t go, you can do better.” Allegedly, this story might be as misinterpreted as Stewart thinking a new Trek would not catch on.
For one, before Star Trek he played Gurney Halleck in the underground but high budget production of Frank Herbert’s Dune. A role that kept him prominent as a companion of the story’s hero Paul Atreides.
He also provided his voice for the English dub of Nausicaa of the Valley of the Wind and had an ensemble role in an alien horror zombie movie called Lifeforce.
He was confident Star Trek: The Next Generation had a chance. His concern was more that, within the first few weeks, someone else would be placed at the helm as it took off.