Very very few actual profitable companies roll their own engines.

Supercell has their own, but it’s because they started before there was anything available.

Indie games make their own engines but it’s more of a hobby or passion project, not something that can employ two dozen people to develop it.

If your game is something that needs it, definitely go for it.

Something like Noita comes to mind

Which is increasingly unlikely.

Kojima is an example of giving dev too much freedom that its basically further putting you into the red had he been strung along for the ride during metal gear solid 5's development and the money spent optimizing fox engine. Theres a fine line between endless crunch time/micromanaging, and letting your devs do work. Take another company like capcom as japanese company dev retention is high. RE Engine is used over several games now. and people agree it performs like shit for open world games.

to put up a few examples, The upcoming Metroid prime 4 is an example when a company gives devs too much freedom. The original japanese studio didn't know what hte fuck they were doing, so Nintendo pulled them off hte project, and gave their project to retro, who was working on the "Project harmony" game, which looked very bad, to the point that nintendo was fed up with the hands off approach and Kensuke Tanabe reinserted himself back as director to get prime's development back into production getting Prime 4 out later this year.

Part of the reason for the huge microsoft layoff that happened a few days ago is mainly because of microsofts more handsoff approach they gave their developers. they gave ninja theory 5 years to develop Hellblade 2 (which is a relatively long time). They gave Compulsion games 5+ years to develop South of midnight. neither game remotely probably paid of their development cost, in juxtaposition to a studio like Obsidian, who has in the same time frame, released 5 different games, some arguably more expansive than the previous 2 studios games, due to being well managed.

and I'm not really pointing fingers here, but keep in mind, its not solely due to unsustainable growth/enshittification and treating devs like shit and endless crunch time causing this problem. It's mainly lack of better people/resource management because there are countless numbers of studios who get significantly more time than they should on a project with not much to show for it.

yes, but tweaking whatever engine they have, still uses a lot of the underlying engines code, which more freemarket devs will use. There's a huge reason why a lot of the companies who build engines in house are in japan, because labor laws in japan makes it so developer retention is usually very high.

Kojima and fox engine is an example of a well designed and optimized engine, but konami didn't like it because of how much millions kojima spent developing both it and MGS5 hence the bad blood between them