IntelliJ is a JetBrains product - I'd be interested in what their revenue breakdown is between "corporate" and "individual" licenses, but I suspect that there are more individuals paying for it than you'd think.
I know I have an active subscription still for PyCharm, even though I've not used it personally since moving to vim full-time a couple of years ago. It's a great product, and I find it extremely useful when teaching people new to Python - the autocomplete is excellent, and there are visualization tools that I've not found a good replacement for.
JetBrains pricing is actually a great case study in price segmentation for enterprise software.
First, they charge different prices for an "individual" licenses vs. an "organizational" licenses. Why? Because businesses have larger checkbooks.
PyCharm: there's a free Community version and a paid Professional version. Python is the most common beginner teaching language, so give the basic stuff away for free. Once you get into "pro" stuff -- sci stuff, web dev, DB stuff -- that's when there's a budget and so people are willing to pay.
WebStorm: Javascript is a mess of an ecosystem and there's tons of free tools out there so no point in JetBrains giving away a free version. However, once you value your productivity and want something that Just Works out of the box with reasonable defaults, that's when a webstorm license becomes something you pay for. Besides, every startup does some form of web dev these days, so larger market.
IntelliJ: Java used to be the go-to language for learning object-oriented coding, so like python, offer a free community edition. Once you dive into Spring stuff, well, you're going there because you have a boss and the boss has budget.
I know I have an active subscription still for PyCharm, even though I've not used it personally since moving to vim full-time a couple of years ago. It's a great product, and I find it extremely useful when teaching people new to Python - the autocomplete is excellent, and there are visualization tools that I've not found a good replacement for.