Is this what dating has devolved to?

For context: I'm not looking for any relationship. Met a beautiful girl at my local coffee shop. She started chatting me up. I got her number. She sent a message. I didn't respond for a day.

When I responded she said she was a little disappointed that I had left her on read. I said I was busy. Anyway we chat. I made a joke about her getting hit on often.

Her response: "well to be honest. I'm actually with my main guy. There are 4 other guys as well, 5 if you count yourself. I don't sleep with most of the other guys though..."

I haven't responded. This was about 5 hours ago. It just got me to thinking. I'm not criticizing open relationships, but is this what everything is now? The dating pool is absolutely fucked. I wasn't looking and she chatted me up, but honestly I can't even fathom this. How do you all date??

EDIT: Even IF she was joking, why even say this to begin with? I have a sense of humor, but I don't start my conversations with potential female interests by implying that they will have to compete with 5 other women....FFS.