I don't think she is being greedy.
A lot of women sacrifice their career to be a sahm and support their dhs as they climb the career ladder. Then, when they get ditched for a younger model, they're expected to look after the children and support themselves, with a token amount of maintenance for the children.
I could be a case in point. Before I married dh, I had a very well-paid, high-flying job with good career prospects. We made a joint decision that I would stay at home with the children and give up my career, possibly returning to it when the children didn't need me so much. Now, God forbid, should dh and I divorce, he still has his very well paid job, but I would be hard-pressed to find anything which paid as much as I was earning when I got married, let alone anything equal to what I would have been earning had I not given up work. Is it fair that he go off with his salary and I'm left to support myself and 3 children on the amount of money the CSA would award?? Yes, I could go and get a "job". But, what would that be? Certainly nothing like the job I had before and, with young children still at primary school, you still have to consider childcare - before and after school and holidays (which would probably wipe out anything I could earn). And this doesn't even consider the effect on the children of their always-there mum suddenly no longer being there for them when they are vulnerable anyway from the divorce.
The divorce settlement should reflect the sah spouse's (after all it could be the dad) lost earning potential by replacing it with some of the earning spouse's salary. This has been recognised with regard to pensions. Why not salaries? Obviously if the sah spouse lands a well-paid job, etc., the situation could be reviewed (which I believe it will be in the Parlour case in 4 years' time anyway).