The problem with that approach is NOT the research. It’s the way to capture it and use it (or not use it).
Even as a much less experienced UXer at the time, it was clear to me that this (quite famous) senior UXer had committed a crime by not understanding that producing a 100 pages document would have meant that nobody was going to read or actually use the research. The research may have been good (it wasn’t by the way, I was the only one that actually read it!) but without finding the right way to communicate it to others and make it visible and actionable, it was just money thrown out of the window.