Don - You should think about posting your dating profile here, we could probably give you some feedback. But also - you need to think a little differently about online dating. You might have to contacts dozens....even hundreds..... Before getting a good response. And you can't take it personally.
For instance ..... The woman who you thought you met all her requirements, and she wrote back that you weren't a match? Maybe you look just like her abusive ex husband. Or maybe there's something else in your profile that tells her you wouldn't match.
I stopped replying to people I wasn't interested in btw, because no matter how polite I was about it, too many wrote back with angry messages. So don't be upset if someone just doesn't answer. They might not be active, or they might not be interested and scared to say so because of weirdos.
My friend is online dating right now, and she showed me a profile of a guy who had written to her. Looked ok until she flipped through his photos, which featured his very nice motorcycle. She nixed him because of that.
See, it's not just that she's a cautious intellectual person. It's also that her husband died of dementia due to a head injury from a bicycle accident. She cared for him many long heartbreaking years before his death, so she's never going to be comfortable with the fear that a motorcycle riding boyfriend would bring up. No judgment on him, it's just not a match for her.
Also, the nature of online dating is that you may be chatting with several people at once, then go out on a date that's a winner, and suddenly you're not active online anymore. It's a little different than dating IRL.