<i>&gt; They focus on one platform, because game programming is more than the graphics API, the hardware architecture and OS are also part of the whole equation, and what means being able to extract every single byte and ms for a few extra FPS.</i><p>Not according to experts who actually work on cross platform games.<p><i>&gt; A publisher that targets PC, XBOX, PS4 and Nintendo has already by definition supported 4 graphical APIs</i><p>That&#x27;s exactly the point. You can&#x27;t claim they are happy about spending x4 times more on supporting their engine on each system and have a very limited ability to share code. It&#x27;s always extra costs. They do it because vendors of those walled gardens limit developers&#x27; choice and artificially force incompatible APIs on them.<p><i>&gt; you can shout to the windmills how much bad lock-in and duplication of efforts are</i><p>They are bad and everyone knows it.<p><i>&gt; no one will care</i><p>Those who care more, work on breaking that lock-in. See what Oxide Games developers have to say about this lock-in idiocy, and don&#x27;t claim they aren&#x27;t professionals.