I expect a lot of parents - both women and men - would like to have much more time with their children. It can't be much fun getting up at the crack of dawn, rushing to feed, wash and dress your child, rushing off to nursery - and then having to rush back after work to avoid being late and incurring late pick up costs. Then the evenings are spent cooking, helping older children with homework and putting them to bed, etc, etc, and weekends are spent shopping and trying to fit in all the chores that a SAHM would have had time to do during the week. Do you really think that people doing relatively mundane and not particularly fulfilling jobs do this for the fun of it? Housing costs nowadays are through the roof and most couples need two incomes to cope with the financial pressures.
Many of us have been stay at home mums for a couple of years or so - that was in the days when you could eat properly, heat your home and just about cover basic needs on one salary. Those days are gone. I returned to work when my daughter was around two and a half because, although we could afford to pay rent and other basic costs, we wanted to buy our own home and couldn't do so on just my husband's salary.
If a person had never gone out to work after the birth of his/her children but was still able to afford to buy two properties (even if one was tenanted a significant amount of money would be needed for a deposit, legal costs, stamp duty, etc, etc), then that couple could obviously afford for one to stay at home. Some people just don't have that choice - they might like to but they don't.