I myself wouldn't know anything about this, but my friend was talking with me about this just earlier today. He said if he was ever looking for something serious again (which he isn't), he would never use a dating app for it. According to him, women using dating apps just want to fuck, not have a serious relationship. You meet women who want to have a serious relationship by meeting them through friends, friends of friends, etc.
Maybe the guys you're talking to / meeting on dating apps have a similar thought process.