Being an actress isn't easy. You have a short shelf-life, so you work like a maniac for those 5-10 years and make the most of it. But when you do take a break, your market value drops, newbies are getting better roles and endorsement deals. There is not much return, either in terms of creative satisfaction nor money. So why will they work at the same pace?
Imagine you worked at a firm and you got paid 1 million a year. You took a break, and for the same kind of effort, you will get only 20% of that money, would you still happily do that job? No you wouldn't. Not unless you badly need that money. Which in case of actresses, they don't. Since they have already made a handsome fortune (an additional plus if they got married to a rich guy), pray tell why would they work for peanuts? They would rather spend that time with family, the life which they missed out on during the hectic working life where they were busy making 3-4 movies a year.
Now is the time to relax, spend time with husband and kids, raise children, go on vacations, pamper yourself etc. Aishwarya is doing this. Of course, if a good offer comes along, she does a movie or two once in a while. It sounds like a win for me.
Regarding getting nannies for kids, I think it's a personal choice. It depends on how attached you are to your children and how involved you want to be in their growing up. Someone like a Kareena may not be that involved which is still ok. To each their own.
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