Engines are not just things you can hotswap. There are a ton of stories about how a mandatory switch to Frostbite really hamstrung a lot of development at EA, especially for BioWare.
One thing for sure is there are way too many variables to claim one way or another how an engine would either hinder or assist in the development process. BioWare had massive issues with Frostbite with 3 games, same story with Amy Hennig's star wars game.
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This is really one of the most understated comments in this thread. A good carpenter doesn't blame his tools. A great carpenter will specialize tools for the job, not to make it faster, but to do the best job with minimal work involved.
Looking back in retrospect, that policy almost ruined the EA brand entirely going into this generation: removal of all titles on Steam, forcing studios to use Frostbite to alleviate royalties, and succumbing to sequelitis. (An honorable mention goes to almost losing that Star Wars license with Battlefront 2, but I think gaming as a whole has a RMT issue that needs to be addressed.)
I'm glad that they eventually came to their senses and decided that picking the right tool for the job was the better outcome and let the developers have more freedoms in making the games.
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I do not think EA ever mandated use of Frostbite, if they did how come NHL is still on Ignite?
They knew they had a great rendering engine, with great streaming (imagine if Star Wars Jedi: Fallen order had been on Frostbite - those streaming pauses, there would have been no end of complaints about how useless the engine was. But now it was Unreal 4 - then it is kind of ok as that is a usual problem...?)
EA probably offer some extra money if a developer used Frostbite and added to its features.
- Things like: DA:I had horses, Battlefield 1 later got horses.
To me it looks like Bioware got some extra resources to develop using Frostbite - carrot instead of whip.
But it looks like they went off tangent for years, then building the actual games in a very short time (guessing EA treated to cancel some of those long running development projects...)
But now we have Unreal 5, shouldn't EA change?
We have only seen glimpses of Frostbite for PS5/XSX, and we do not really have Unreal 5 yet...
Frostbite is often the engine that is first to deliver new features in actual games.
EA back to release on Steam is probably Valve as much, they took a premium for their service...
That was kind of OK while most games were physical sales with their own overhead.
When most game sales went digital then EA is big enough to handle their sales themselves, after all you can put your game zip on a generated shop webpage...