It's called Brook's Law. It takes a lot of time and effort getting people up to speed, and that takes experienced devs away from coding. You also have to get them credentialed, teach them the tools, need extra code reviews/testing/bugfixes while they learn the quirks and pitfalls of the code base, etc. In the long term you'll be able to get more done, but it comes at the cost of short term agility.
Maybe "credentialed" wasn't the right word. I was thinking of software licenses and access to third party tools and systems. Probably not as big a mess in game dev as it is in government.
Like getting 9 women pregnant and expecting a baby in 1 month ( sh.itjust.works )