MacMacMac Welcome!
CyberGene is correct, at least at this smaller scale and being free to start from scratch with new software on modern hosting solutions. I've read most of CG's posts on this matter, learned a lot, and got a huge head-start.
Of course, Frank had 25 years of legacy to deal with and was most likely running PW on dedicated physical servers. I think he also paid someone to manage it.
VerticalScope have plans to move PW to Fora to cut their costs. The migration is probably causing them some trouble. They've seriously botched this in the past with other forums, doing incomplete migrations, losing posts, and locking former users out. Funnily, I was able to migrate all my posts over from PW over to P|T without even having access to the backend. The ad situation on PW is untenable to me.
P|T is essentially running for free now, because it's on FreeFlarum. This has ups and downs. If we ever get closer to the scale of PianoClack, then I would first move to shared hosting on Namecheap or DreamHost, and after that consider VPS if needed. Cost would be in the few dollars per month ballpark as CG says.