Depends on the firm.

I work for a more technical focused niche consulting firm, and one of our specialties is large IT implementation project recovery. We are extremely successful, but it's dirty work that isn't super advertised.

It is for a lot of executives, especially ones which are clueless about technology or who do not have a technology background but were promoted and told to "fix the TPS submission and reporting system!". These characters are typically corporate politicians who are great at talking but couldn't manage a team of 3 to boil a pot of water.

They love consultancies. It's a total roll of the dice if their projects are successful or not. I've seen it go both ways.

As noted by another commenter, they employ 500k people and execute on thousand of projects per year. Most of those projects are likely success stories to some degree.