Personally, I wouldn't mind paying a small fee for a great note-taking app, but I would like to be able to share some notes with my mom and with my partner. But they wouldn't want to pay for it, as they wouldn't use the app as much.
I hear syncthing is good for this, but obviously it's messier on iOS.
I just know that $8/mo for sync is too much. You can get Office 365, or Google Drive/Dropbox with a TON of space for that price, and that space is usable by lots of different things.
Plus you constantly run into issues with compatibility between the sync app(s) and the Mac/PC/iOS apps you use to edit the files.
Nothing prevents me from running that exact same setup for Obsidian for free. But I’d much rather pay $8/month and not have to deal with server backups and maintenance, compatibility, or all of the other issues.