JWK hit all my reasons.

I suffer severe bone loss, arthritis, and cancer. One of my docs is also a range buddy. He saw what I was going through with my 1911 .45acps, and decided I was done with them. Between him and the ortho surgeon, they convinced me. I moved to 9mm 1911 as my primary, and have added some / sold some since. I got my first 1911 in 1968, so that was it.

But I grew up with the idea that a 1911 had to be a .45. Took some doing to convince me that 9mm was valid, but that's where I am today.