It's certainly profitable, if it wasn't profitable then porn sites wouldn't exist. Very few people are going to spend their own money to give other people porn, so we would go back to USENET and such with people sharing porn on existing services.
With that said, you got to figure out if it's worth your time as profits have gone down drastically over the years. Shoot like 15 years ago I had a site that was literally a Google search bar and a photo that changed daily of a lady in a bathing suit; I even had it running on Blogger.com using Google Ads as back then they didn't care. Was making over $100/day for literally seconds of work as I'd just upload in bulk and schedule the changes to happen automatically at midnight. Today that would be almost impossible. You'd have to do far more work these days and it's only getting harder.
But you also got to take into account skill. Porn can be done by basically anyone to an extent; if you want to build a tube running KVS you'd need to know a bit about Linux and servers, but a simple re-upload method can be done by anyone. There are more lucrative ways to make money online but they either involve more risk, more skill, or both. Porn is almost no risk (unless you're in a country where it's outright illegal) and almost no skill. It's profitable, but it might not be the most profitable thing you could do. Just divide the numbers, the global porn industry is said to be worth 97 billion. That's a lot of cash, don't get me wrong, but that 97 billion is split by all the players. The largest of the internet players is MindGeek, the owners of PornHub, RedTube, Brazzers, PornMD, XTube to name a few, is "only" worth 750 million because that 97 billion is divided by so many people.
You can certainly make a living in porn, but if you want to be baller rich that's not very likely. Those are just the odds with the overall money being divided by so many people.