You're suggesting companies build teams of amateurs with the hope that they can all pick up the skills amongst themselves as they go.

If you have to for example build a new operating system kernel, or a new compiler, or implement a machine learning system, hiring a bunch of well-intentioned smart people with the vague idea that they can probably figure it out as they go is a bad idea. You sometimes need someone with a track record of being able to do the work you need done.