My impression is that people who claim PHP has not cost them development time have simply never looked at alternatives that solve many of the problems.
Excluding the obvious issues caused by bugs that are a natural part of any programming language's development, security problems are not caused by the language chosen, but by the developers themselves.
If your statement were true, then by that measure making a program in assembly would be as safe as doing it in C#. Evidently, it is not. Languages make certain idioms easier or worse, and they have a culture of security or they do not, which is reflected in development methodologies, libraries, and code samples.
PHP fails massively in all those regards.
Putting PHP in the "inadequate corner" or trying to convince oneself that it is lacking in features is just an easy excuse.