Because it got 7/10 average review scores and didn’t sell as well as GTA. Then GTA3 (and its immediate spin-offs and eventual sequels) came out and started breaking all time sales records. So retroactively, GTA 2 was “a mistake” for not being GTA 3 two years early.
But like the guy says, the point of the article even, is that you don’t create run away successes without experimenting on the formula to find what’s good, without “failures” like GTA 2 to learn from.
The book is very good! I happened to catch wind of it right after it came out. Its a great mix of Visitor’s personal experiences in TV, and her research and interviews with many women who’ve worked in Trek over the years. She writes well and the stories are both personal and educational about the history of the show and the medium.