I agree in the frictionless vacuum sense, but I think you're missing an element of how firms work.

Just spitballing, but it's incredibly non-trivial to both aggregate skilled labor and organize them into an effective entity. Being eager about tearing down and spinning up these organizations to keep each entity single-purpose seems like it would be a lot less efficient (and competitive) than taking advantage of an existing well-run organization to do things that are somewhat related.