> 1) Porting costs are not per game but per engine, which can be shared between multiple games. True but they're still big enough that that cost is significant

> 1) Porting costs are not per game but per engine, which can be shared between multiple games. True but they're still big enough that that cost is significant. Even when diluted across game budgets. > 2) The majority of costs is ongoing support, not writing to a different API. Ongoing support is still required for writing to a different API. Ongoing support involves (a) updating in line with API version changes and (b) updating API-integration abstractions in line with game engine API updates. Supporting multiple APIs adds at least some amount of friction to every code-change. There's also the increase in cost of testing every engine code change across multiple graphics APIs.