You're definitely not harming him by going with his rhythms and needs!
I met a woman on an airplane once, flying with her 3 DC: 12, 5 and 17 months. We got to talking about sleep, and she said DS1 was a great sleeper, as was the youngest. The middle DS, a lovely little lad, didn't sleep through the night until 3, and even at 5 yo she still had to lie with him each night. She was so matter of fact about it -- different kids, same environment and parenting, nonetheless different sleep needs and patterns. No big deal. She actually enjoyed it as it ensured she always had one on one time with the middle child. I found it so reassuring.
I asked all the same questions as you. I'd look around at parents having a leisurely lunch while their baby slept in a pram and think why won't he? No exaggeration: DS never did that. Not once. He wouldn't sleep in the car, pram, Moses basket, cot, "snuggle nest" thing we got for co-sleeping, swing, etc. He'd sleep on a person. The end. Once I quit fighting that and let him get on with what did work for him, we all coped better.
He has always been super active and engaged and still finds it hard to switch off for sleep even now. It's just how he works.
If it makes you feel any better, although sleep has been challenging, lots of other typical infancy and childhood things have been a breeze: potty training and getting rid of his dummy, for example, were complete non-issues. It helped me to think of it as sleeping (and eating, really, as he is on the picky end of things) being less than ideal but everything else being easy so it felt more balanced.