This becomes even more unrealistic when you introduce the concept of a “homemaker.” Usually that involves kids but it doesn’t necessarily have to. If a couple decides to have one get an education and a paying job and the other has responsibilities around the home then that is how they’ve chosen to divide their labor. You can’t just maintain a balance for your marriage but come divorce time say “oh well, they can take care of themself.” The working spouse has a massive head start and the non-working spouse has (possibly unwillingly) had a massive downgrade in QOL forced on them.
Alimony seeks to create equality. Either equality in success or equality in hardship. It probably isn’t a perfect system and I’ve seen instances where it is massively abused but I don’t think the concept or execution is overly flawed. Perhaps too many adults are jumping into marriage without fully understanding what it means and how it might end.