Worked on PHP on-and-off for more than 15 years. Jobs in PHP can sometimes pay well, but the PHP labor market is fairly saturated, so you're more likely getting underpaid than well-paid.

Here are some of the reasons I don't use PHP anymore:

1. Code bases often written by near-amateurs, so almost always a headache to work on

2. Terrible type system (and unpredictable type coercion) mean that the code has to be written with great discipline or it's going to be buggy

3. Inconsistent signatures of built-in classes/methods/functions means that it's almost impossible to remember anything, so you need to consult documentation (or inline completion) constantly

4. Very generally, a community that likes magic (see: Laravel) -- ease/speed is prioritized over correctness/explicitness, which means maintaining large PHP projects is often a nightmare