I have not done the exact math before responding, but to get a collision is far beyond the scale of getting hit by lightning multiple times. I think it would be more like getting struck by lightning every day for a year or a decade kind of thing.
Yep. It is very unlikely. There are awfully lots and lots of numbers in a private key.
But, anything can happen. And sometimes amazing things do happen.
It is one thing to win a lottery twice and another to trow a can of toothpicks on the floor and them all stacking up vertically one on top of another and staying balanced like that.