Honestly, assembly language bitrots far faster than other programming languages. In my lifetime, the only thing that really comes close to qualifying as "compiler language syntax/compiler planned obsolescence" is Python 2 to Python 3. In contrast, with x86 alone, there's three separate generations of assembly language to go through in that same timeframe.
Look, I work on compilers, and I have no idea what you're even trying to refer with "planned obsolescence" here.
And 5/10 years is a very short time in compiler development planning! Prototypeless-functions in C were deprecated for longer than some committee members were alive before they removed from the standard, and they will remain supported in C compilers probably for longer than I myself will be alive.
