Indeed. It's the best (shittiest) way to deploy code on as many people's desktops as possible.

Ecactly the environment JavaScript exists in (the open web) is so accessible and awesome, which is why it's popular, and that awesomeness rubs off IMO

There is another - unique async nature from the start. That's why it made its way into node.

It is not popular the same way PHP is popular in any capacity. It really is a unique useful efficient language.

So what's your excuse for the popularity of Java, C++ etc?

I think the main reason for the popularity of object-oriented languages is that the design corresponds more closely to the physical world, which makes it easier to reason about the architecture of the software.