As someone who has been designing, writing, and operating high-performance systems for decades, I can guarantee you that it does not boil down to "laziness".

Everyone starts with the best of intentions. malloc() and free() pairs. Then inevitable complexity comes in - the function gets split to multiple, then across modules, and maybe even across systems/services (for other shareable resources).

The mental overhead of ensuring the releases grows. It _is_ hard, and that's most definitely not a lie beyond any trivial implementation.

Surprisingly "just design systems that manage their memory correctly", as you said, is a very legitimate solution. It just so happens that those systems need good language support, to offload a good chunk of the complexity from the programmer's brain to the machine.