I was not trying say that security fixes cause breakages. I was trying to suggest that security fixes cost money and therefore old APIs would get withdrawn for

I was not trying say that security fixes cause breakages. I was trying to suggest that security fixes cost money and therefore old APIs would get withdrawn for monetary reasons (if they weren't simply replaced by something new and shiny which is the usual reason). If old APIs required no maintenance it would be fairly simple to leave them around. However, APIs are built on an ever deeper stack of APIs that go all the way back to the Operating system and through internet protocols (APIs) right across the internet. Each API gets updates and fixes and things get deprecated. Bit-rot sets in and things stop working. My original comment was suggesting that if everyone just left their old APIs around forever then the world would be filled with unpatched APIs with security flaws and I was not sure that would be a better place to be than the world of bit-rot that we have now.