Come on. First of all, just because a lot of people use PHP doesn't make it good.
Who cares? A language being good or not is an irrelevant nerdcore detail that businesses - the things that give you money in exchange for work - don't care about.
C++ is a terrible language and yet it's also the single hands-down best language to use for AAA game development. C# has all kinds of mistakes and nonsense in it that we're stuck with since it's the dominant general-purpose applications language (and the second most widely-used Web language). Python had to have an incompatible 3.0 release because of the mistakes made in older versions. Ruby has gone through several major upheavals. JavaScript is widely considered even worse than PHP and yet is unavoidable in Web development. Java is widely hated by many experienced Java programmers. Perl is considered super difficult to read even by its proponents and also had its own failed incompatible redesign in attempt to fix it. Shell script is so bad that practically every Linux programmer has written their own shell.
All languages suck and are terrible, all libraries and frameworks are terrible, all game engines are terrible, every Web application is terrible, every non-trivial project is chock-full of terrible code, and life goes on.
To quote Bjarne Stroustrup: "There are only two kinds of languages: the ones people complain about and the ones nobody uses."
If you haven't realized this yet, you're too new to programming.
Second of all, PHP doesn't pay a ton! Seriously! Python / Ruby pays way more than PHP
A tiny bit of active research belies that. The languages all pay around the same. A PHP programmer will average around ~$95,000/year, roughly the same for Python or Ruby or C# or C++ or so on. An entry-level junior programmer will make less. An experienced senior developer will make more.
Said experienced Web developer will know PHP, Python, C#, C, Perl, JavaScript, SQL, shell script, how to set up and secure a LAMP server from scratch, and the average air speed of an unladen swallow. They'll be able to tell you why PHP sucks, why Python sucks, why C sucks, why Linux sucks, why databases sucks, why the Internet sucks, why vacuum cleaners suck, and then will go get the job done in whichever technology is used by the rest of the team without whining about it.
Since the OP is asking about how to get started, though, my answer remains: if you want to jump into the Web quickly, start with PHP and diversify your language knowledge after, but diversify it as much as you possibly can as soon as you can.