> Meanwhile, in the real world, network and kernel programmers have been using some variant of u_int32_t since forever to ensure that they can parse network packets and driver data structures by copying or even casting things into structs.

And compiler developers in the real world are also increasingly nervous at this state of affairs. The subset of C that works in practice is unspecified. There are plenty of optimizations that compiler developers would like to do, but they don't because they're worried about breaking some code somewhere that relies on undefined behavior (like the code you're talking about). At the same time, performance competition pushes compilers to exploit undefined behavior more and more heavily. There is (IMHO, well-founded) worry across the board that this situation is not sustainable. Experience with this problem motivated the design of languages like Swift, which try to clamp down on UB drastically—which also has the happy side effect of making articles like this one inapplicable.

Undefined behavior has already had practical consequences, such as security-sensitive VM escapes: https://bugs.chromium.org/p/nativeclient/issues/detail?id=24...