Well at Wimbledon the rain is part of the challenge. You must play the other players AND contend with the weather. It is part of the tradition.
However, money talks... and with the weather interfering with the TV coverage as well as the attendence, I understand that center court will soon have a closable roof, probably to be followed by court 1 in the future.
The AO has one on center court and it has served us well in the past few years.
Wimbledon is next.