I am equally drawn to "Yes I absolutely would" and "Absolutely not".
I had my DC young, I'm 30 now and when I'm 50 they will all be in their mid to late 20's. I can fully imagine wanting to have one more baby. It would definitely only be the one though.
On the other hand, right now me and DP are in the thick of parenting, we don't have childcare options so we never get to do anything together that doesn't involve the kids. As much as I love family life, I do spend plenty of time dreaming and planning of our future where we are less needed by the kids and can start living life together again.
My dad had me at 58; he lived until 84 despite poor health and obviously because he was so old when he had me, even though he lived to a reasonable age I was only in my 20's when I lost him. Despite this, I think even though I was young, I have processed his passing well as he didn't die prematurely or unexpectedly.
I think if I was in very good health and the world wasn't in tatters, having a baby at 45 would be quite nice. That's 15 years from now and my youngest will be 19.
You've definitely got me thinking with this one, OP!