Short answer: no.
Long answer: nope.
How many applications do you think are written in PHP? How many man hours do you think will cost to replace those applications that millions if not billions of users use? Could you replace them with an exact copy (HTML rendered page that looks exactly like the original) of what they are using?
Realistically speaking, you’re going to waste more money and time to find such a project for switching every single user to a Python based alternative platform. And let’s not forget, those “alternative” platforms might not even work the same way nor work as efficiently as those that are written in PHP.
Not just that, you want to replace PHP? Then you’ll not only have to replace the code base, but also replace every single PHP installation on every single operating system ever created. macOS comes preinstalled with PHP, some Linux distros such as centOS come prepackaged with PHP.
People only usually mention Facebook or WordPress when they talk about PHP, but ever wonder what language PornHub is written in? You might want to double check. Not only that, some bank’s websites are written in PHP. Ever wonder how the game you play everyday has such a really nice and seamless [forum] experience? That’s because majority of them are written in PHP. A lot of popular gaming forums run on either vBulletin (written in PHP) or PHPBB or some other variant of PHP forum software.