Honestly "diversify" is not something I had ever considered before the last recession, and it runs contrary to most popular advice in consulting around finding a niche, but it becomes very apparent after you've weathered the ups and downs of the consulting business over a long time period.

If you look at any of the major consulting firms (ex: Accenture) that have lasted decades, you'll see that they have their fingers in many different unrelated areas and industries. "Niche" in the short term is a great way to build up clients, but stick narrowly to a niche over too long a time scale, and it becomes an anchor.