>There's a reason major software vendors provide professional services. If their customers could reliably hire and (most importantly) retain experts on their own, they wouldn't need professional services.

This. As a tech person with decades of professional services experience in the tech space, I couldn't agree more.

Generally, there are three reasons why corporate entities hire professional services (this isn't limited to tech stuff either):

1. There's a specific need for design/implementation expertise where FTEs are either not readily available or are unnecessary once the implementation is complete;

2. The internal group in favor of a particular technology/implementation wants/needs validation from "experts" to get full buy-in from management;

3. Professional services are brought in to "validate" existing project plans/implementation details as a CYA against project failure (e.g., "the consultants told us this was the way to go. They were wrong, not us.") which (both bringing in consultants and project failure) happens a lot more often than you might think.

Those are all valid points. However those are also the counter argument: eventually the cost of all those services is more than the cost to do it in house, or find a competitor.

Yeah but again, it's most often not about the money...

I work for a large enterprise and we pay or retain vendors to do things for us all the time, at a much higher cost than it would be to do it in house, because we cannot find/hire/retain the expertise to do it ourselves, and at some point we need to get the work done so that other more mission-critical work can happen to drive the business forward.

Plus, there is value in paying someone to make the find/hire/retain part their problem instead of ours.

We buy the reliability of getting the work done in a timely manner, on top of the work itself.