And you might get PHP running in almost all servers, but that says nothing about all your dependencies such as mail servers, message queues and the like. So the fact that it runs everywhere doesn't actually mean that much.
Meanwhile, recent attempts at fancier competitors (like Ghost and Discourse) have completely failed to capture the marketshare of their PHP based counterparts because they're just more difficult to set up for the non technical individual or company. Their creators put image (aka a more 'glamorous') tech stack above ease of use, and paid the price.
PHP's ease of deployment is basically why so many of the larger CMS systems of today got popular at all.
you have to realize php is also incredibly insecure as well. chmod 777 on install instructions? on a shared webhost server? this really was and maybe still is the "thing".
the nature of being able to upload a php file to server on the public docroot makes the language always prone to hacks. sure there have been improvements with things like mod_suexec and fpms but this now makes things that usedto be easy now hard, ie htaccess and rewrite rules.
This is not true. We got AWS Lambda and friends, which let you write PHP in any language.
After all, in 2002 (the date of that Q&A), you could already deploy Perl or Python scripts by "simply uploading code to a directory", if mod_perl or mod_python was installed by the hosting provider.
Coordination problems are difficult.
It's not anymore, and hasn't been for awhile. Here's one example:
Solutions based on Node.js can be stand-alone.
(Hyperbole that hopefully illustrates my point)
The only thing where nginx might help performance-wise here is static file access (of eg. static web assets such as CSS or static HTML).
It was easy to get setup and start programming in the 80s. That allowed you to spend time/energy on the complex logic you needed to write the program. Most programming is so much easier the level of math required is so much smaller and most websites are simple crud. Why are we making the setup process more difficult? Do we really need a gate keeper?
PHP is the only language with almost universal support among web hosts. It can run on basic shared hosting plans and on nearly every server. It can be deployed by simply uploading your code to a directory on your web host. Sure, it's a widely criticised language (even within the PHP community), but it still accounts for the vast majority of server side code (80% according to some sources).
What's baffling is why other languages and so many developers are blind to this problem of easy server install. They think it's a non-issue.
Prolific blogger and programmer, Jeff Attwood ranted about how he disliked PHP in one of his blog posts, but recognised that:
"If you want to produce free-as-in-whatever code that runs on virtually every server in the world with zero friction or configuration hassles, PHP is damn near your only option."
To broaden choice, Attwood argues we should:
"build compelling alternatives and make sure these alternatives are equally pervasive, as easy to set up and use as possible."
That was written in 2012. (https://blog.codinghorror.com/the-php-singularity/).
It's 2017 and what's changed? Nothing.
Having a ridiculously easy web app installation process for servers would unlock countless opportunities for developers to reach more users or customers. And it has, for many PHP open source projects and products.
Want your customers to self-install your software? Good luck getting them to do that easily with any language other than PHP.