Measured how? Being good enough or not for which of a million uses? Without that these statements may well be true for the author but meaningless for the reader & potential user.
(Avoiding allocations is frequently a reasonable idea when minimizing latency, for example - maybe not for you).
I think it's wild how people insinuate I'm a fool if I literally say it never is a problem for us. I think it creates a "boy who cried wolf" problem if you always harp on stuff that doesn't actually manifest.
In general, I'm with you on memory allocation. I recently rewrote our animation system to not allocate memory at runtime, but to say "never use std::vector because it's performance is bad" is a statement I can't get behind.