Forums aren't dead. Mine has just accepted it's 89th member. It's about opportunity. Peerlyst for example was a huge forum I used to be a member of, but left and deleted my account when they failed to even take the most basic of steps to prevent trolling. An incident quickly escalated, and went way beyond what should have been one comment at the most.
That side, I've been biding my time, and honing the experience on my forum. Peerlyst has announced its closure at the end of this month, so I've been busy accepting their users who seem very happy to also move their content to mine.
Much of this really depends on content and engagement. If you keep a forum busy, and members are engaged, then you have nothing to lose. The more users you have, the greater the momentum, and overall, the more content.
Features are also important. Back in the days of BBS (I'm showing my age here), you simply had post and reply functions and that was it. Things have moved on since then, abs with the onset of mobile apps, PWA etc, there's much more than can be offered.
On the hosting side, it's not expensive at all. I don't use CPanel and host my own VPS without any difficulty. It's mostly about commitment and perseverance.