Also not strictly true - this is enough for some version of PHP development. The last PHP app I was developing was running in the same mode as the whole compan

Also not strictly true - this is enough for some version of PHP development. The last PHP app I was developing was running in the same mode as the whole company's infrastructure was developed and running - one puppetized Vagrant VM for the code and one for mysql, and sometimes a few more for other services. Sure, even if you just want to abstract the stuff away from your host machine you could reconfigure stuff to run on one VM - but that's again diverging from production. And in the grand scheme of things we were working on several different vm types a lot more than only on this PHP app...