It takes a certain ambition to create a new own engine. Hideo Kojima created the Fox Engine during his last years at Konami and while Konami doesn't use it anymore Kojima used the experience of creating that engine to figure out what type of engine he wanted for 'Death Stranding'. I am sure it is worth it to create a new engine if the company plans on releasing game after game in quick succession.
Capcom is now using its 'RE Engine' for all their new titles (Resident Evil Remakes. Monster Hunter Rise, Street Fighter 6). But if a game set for release is just a one off with nothing else planned from it than I am sure the publishers and developers would rather just use something easily accessible for their workers and company. At least that is how I understand it.
Your post was an interesting read! Thank you for sharing your thoughts. Maybe if the coding engineers were allowed to share foundation code or even lines that could help with universal functions for an engine there would be a variety of engines but if the company is netting in a profit from everybody their engine I am sure they want to protect their property/assets.
Yes, but the big reason why I made this post is because Unreal Engine is not perfect. And game engines these days should easily be accessible to anyone else, even the in-house ones. A lot of software has made changes because of the competitive market, if Epic took the majority share, it would stifle that kind of change.