Decompiler space probably has a few tens of millions in revenue yearly, yet writing a good decompiler is quite a lot of engineering effort, and you are not going to spend tons of money and effort to capture a measly 10m market, you'll rather be the next uber type thing that targets a much bigger market.

Hence HexRay can get away with not doing much and just collecting license fees from existing customers yearly, as there isn't a better alternative anyway.

One thing Hex-Rays has that Ghidra doesn't (and cannot) is amazing support. Back when I had a license at work, I could report bugs and literally get a fixed binary back a couple of hours later.

They're both amazing, they're both quirky, and they're both buggy. But one is free and the other has its support. Pick which one matters to you :-)

It's been a while since I needed to do any serious reverse engineering work, but I do remember IDA pro having support for a range of obscure CPUs, not sure how ghidra compares on that front these days.

Ghidra still mostly relies on community plugins for obscure platform support. It's ~OK but less than ideal.

Ghidra outstrips IDA Pro in the number of architectures it supports.

One of the major categories of users is people in the warez scene, all of whom are pirating it. The only other one is security researchers, which is a pretty small market.

And backward engineers, including porters and students, and code recoverers.

And especially, software tweakers and improvers. Not all software is open source.

IDA Pro was an amazing disassembler and accompanying set of tools - top of the pack for quite a while.