I disagree here, making an engine you'd sell must be top notch in every aspect (or close to), an in-house engine only needs to get the job done for your game. Probably two orders of magnitude in needed workforce, depending on your needs ofc.

From Software and Hideo Kojima would disagree. The highest form of passion for your game is to create an engine that gives it the exact gameplay formula you want it to have.

Of course corporate greedfucks cannot understand this, they only care about how many villas and yachts the profits will get them.

It’s not really that great of a business.

Epic is estimated to have made $275M revenue on Unreal engine in 2023, vs $4.7B on Fortnite

Unity made $614M revenue on engine & tools in 2024, in ads and monetization they made $1.2B

These are stable industry standard engines, if you start work on your challenging engine today it’ll take years to develop, gain game-developers interest and trust. And still you’re competing with giants that use their engines as loss-leaders.

The advantage of making your own engine is that you can specialize for your specific gameplay.

Then you only get a big geneal use thing like Unity again.