My understanding is that the majority of PHP jobs out there are maintaining old, outdated, and bad codebases using an old version of PHP so a lot of people just don't bother.
There is probably some truth to this. Every single contract I have been offered in the past 2 years including the one I am currently working required PHP5.6 & 7 knowledge, git, composer, JS, the latest JS frameworks, etc. Start the job... PHP5.3 codebase w/ some old jQuery. Its an absolute nightmare. I have to go home at night and write in PHP7 just to maintain some level of sanity or I'd have to cry myself to sleep. The only thing that makes the job tolerable is that I was able to load xdebug on the dev environments (though it doesn't always work b/c of all the redirects - it still is good enough to get me 90% of the way there).
