I’m married so definitely not online dating but did on and off for years in between relationships before I met DH. I’d say out of the 4 years that I dabbled on and off in it, I actually only found 2-3 people that I had ‘online chemistry’ with, and that also translated into when we met IRL.
All of these men were very good looking, tall, popular, intelligent and very successful in ‘professional’ careers. They had women drooling over them IRL constantly so why they had to OLD I don’t know (they definitely weren’t married/ in a relationship) But then (I’m aware how big headed I sound here 
) i had a lot of male attention IRL too, had lots of friends and a good social life, I think it was just the lack of meeting anyone with relationship material status on nights out and boredom for me which is why I did it.
What I’m trying to say in a roundabout way is that I met and spoke to a lot of bores too if I’m honest. It didn’t surprise me that they were OLD no flirting, no banter, stagnant, dull conversation, bleurgh.
And there were also so many that seemed to want a pen pal rather than to actually meet up. Like I said, there are very few men OLD, IME that are witty and interesting for long periods of time online. There will be some that are better IRL or that you’ll have a better connection with IRL so you’re best just exchanging a few messages and then so long as you like the look/ sound of them, arranging to meet.
Endless messaging is just a passion killer IMO.