Every single person I've ever heard talk about Unity or Unreal in such an aggressive way was completely clueless about software development. They all have high hopes of making the best game/engine the world has ever seen yet are stuck in the planning phase. Either that or they're gullible gamers who watched too many youtubers.

The reality is, every single engineer who built the very optimized engines you my have in mind (that power a few specific games at most) have great respect for Unity and Unreal.

Game development is a small world, people know each other across companies, share tech stuff on Twitter and go to the same conferences.