I doubt it was the limit screws. With an index system that shifts fine for 2 years, the limit screws don’t mysteriously move, especially to the extend need to drive a derailleur, against spring tension, with the shift cable into a wheel. It just can’t get there.
My guess... really crappy shifting under load over time caused the chain side plate(s), one or more, to flair out and that is what caught the derailleur and dragged it into the spokes.
A good chain can still work in the worst conditions, a flared chain will destroy the best drivetrain money can buy.
John