The purpose of hiring them is to make them come to the conclusion you already have, so when it goes well you get the credit for doing it, or if it goes sideways you can pin the blame on them.

Or, alternatively, there are so many companies that are weak on tech they pay for someone else to guide them.

Most companies are not _just_ tech companies and don't have business analysts, consulting analysts, solutions consultants, software engineers and DBA's on staff.

Many, many, many companies are very happy with the consulting firms they hire.

Of course, those are the consulting firms that aren't publicly traded and in the news all the time (for all the wrong reasons).