It seems that you're talking about a code that is exposed to some third-party clients where you need to maintain compatibility. This is, of course, a valid conc

It seems that you're talking about a code that is exposed to some third-party clients where you need to maintain compatibility. This is, of course, a valid concern, and you're absolutely right that this layer, exposed to third party clients absolutely does need increased level of friction. However, most applications don't have any such exposure, all of their code is consumed internally. And even when they do, their external API surface which is actually exposed as some REST or ABI is minuscule in comparison to all the internal APIs — method calls and types that are never exposed anywhere. I think that this problem, which is certainly a valid one, should be solved with methods which would not negatively affect developer experience of working with 99% of all the completely private APIs that don't need to be backwards compatible.