I spent years lifting weights, and I also believe that most people could deadlift 200lbs from the start. I also believe that once they learn technique, they could increase that to at least 250 without putting on any extra muscle. A big part of lifting something heavy is knowing the right way to lift and which muscles you should be using to do it.
Hell, if you can jump a few times and do two or three pushups, you've already got the muscles needed to deadlift more than your own bodyweight.
Fair correction, I was going off the parent's statement of males under 40.
I'm talking one rep max after warm up. A beginner would be hard pressed to rep nearly that much. My one rep max when I started was 185 and increased to over 300 within a few months. After a year I was maxing at 415, that's where I stopped going any further. I have had (and have seen) massive gains in one rep max just from learning good technique and getting your muscles used to lifting for a week.
I've had +25 lbs to 1RM simply by using reverse grip.
I posted a link to an article that shows the 50th percentile is around 180lbs for males. People always underestimate their deadlift. They don't realize they're using some of the strongest muscles in their bodies.
I think people also don't get a true 1RM on DL because they're scared of hurting something (and admittedly n00bs that aren't cautious often hurt themselves). It takes a month or two of getting comfortable with the technique before you can take your first accurate 1RM.
Hell, if you can jump a few times and do two or three pushups, you've already got the muscles needed to deadlift more than your own bodyweight.