Could a person stay single their entire lives and never date or marry?

As long as they're happy... I know someone who is nearly 70 and enjoying life, never married or had kids.
I am not single, but sometimes I wish I was... sometimes I just want to live on my own like a hermit... if only I could afford it...

I know a number of older people who have done so

Sure. My uncle did it. He was perfectly happy.

Why not?

Very common

I might end up that way.

Yes they can

Yes. This is not news.

Easy if you don't want one

Yeah, you can.
You can also drive a car with your feet.
Doesn't mean it's a good idea.

yeah just be the person nobody is willing to lower their standards for.

Yes