To play devil’s advocate a little bit, being required to make every new API publicly available right away can be a real pain in the rear for the first several iterations of these APIs, for both first and third parties.

A common pattern in Apple platforms has been for APIs to be private initially, then made public 2-4 major versions after introduction, once the bulk of the design churn is over with and it can remain relatively stable. Essentially, they focus on making it functional and shaped correctly and then make it public once they’re satisfied. They don’t do this with every API obviously, but have with several.

I think the DMA would be stronger if it had a “beta clause” that allowed that form of development for some stretch of time (a couple of years maybe) after public release before requirements kick in. This way companies don’t have to try to juggle making the APIs functional vs. fit for public consumption.