Your intuition is right. Some of the popular public VPNs are high-margin snake oil businesses. Even if you’re paying $2/mo (like for PrivateInternetAccess or SurfShark), that’s likely at 70%+ profit margin for them (even with multi-hop, adblock, and other bells & whistles). It is for nothing that VPN subscriptions are notoriously hard to cancel. And, I run a VPN service myself (but not with UI dark patterns, not yet)! 
What you’re paying for is mostly the value you derive from using it (which may be pays for the said VPN provider’s marketing budget). If you know multi-party relay setup covers your threat-model (or worse, their marketing copy has you convinced it does), then well, Obscura (and may be Nym, too) is one of few MPRs around that seem super serious about what they’re doing.