His first serve is so bad now and he almost always loses the point on his second one
Well that isn't true for a start!
One factor is that he has not played many of the younger opponents and it often takes him a while to get used to their games. With this tournament in particular the rallies are very long and exhausting so that the younger players may have an advantage over Andy in the latter stages of a match.
After all, I think Andy was competitive. Not everyone can be top ten.
I agree with all of that counter-puncher.