It is because tennis is different to rugby, football etc.
For example Manchester United play at Old Trafford like 50% of their matches and they train there etc. While a tennis player from Australia plays at Rod Laver Arena like a couple of times.
Football etc. actually have a "home" while tennis you don't.
A tennis players home country still is "home". Familiar environment, language, food, friends and family, crowd support. I would say most players enjoy playing in their home country a lot, with some exceptions who dont like attention and pressure, such as Mauresmo and Gasquet.