I'm married now, and never used any parasocial platform OnlyFans or another, but trivializing the problem of young adult loneliness is either ignorant or condescending.
A large fraction of young males don't have anyone to "take out for a dinner", or at least have no idea how to initiate that. You may scoff at that, but I certainly wouldn't know how to do it, and money was not a problem. Paying for human connection, especially online, was tempting.