The companies that operate them are incentivized to keep people lonely to increase your usage for a chance you spend a little money eventually out of frustration or desperation.

Bots, catfishing, paid actors... When I attended university a while back, dating sites and their proxies unabashedly published printed ads on the blackboard for "chatting up people online." A good opportunity for students to make some money on the side as you can chose your hours quite freely. You'd never get to meet the people you chat with, of course, as that was never the intention.