This is a perfectly reasonable setup for these agreements. If your spouse is not working and you are married, it is either through mutual agreement or inaction. Fundamentally a marriage is about mutual navigation of life. If you are failing at this, a divorce is an option, as are other avenues (marriage therapy, etc). The point of a* marriage contract working this way is exactly the flip of it: to go extreme, if you are abusive in the relationship and will not let your spouse out of your joint home, and they eventually manage* to get a divorce, they are now attempting to operate without the last N years of work history. How does your spouse get back on their feet now? The person who is taking advantage of the marriage can be the breadwinner, and the breadwinner (if there is only one) provides the means of survival.
Marriage is a life plan. You say that jointly and indefinitely, you will navigate life together. This means both of you are (should be?) planning with both of your current and future states in mind. If one isn't working, they are planning on the other's income to continue life. It's perfectly reasonable for the baseline of a marriage contract to be shared income and a reasonable time to adjust to the loss of shared income should you get divorced (and that this reasonable time grows the longer you are married). You might say, half of the duration is too much! Then propose something better, and adjust the contract accordingly. You might say, that jeopardizes my wedding, it seems like I don't love my future spouse! If this is important to you, that is something you must work through.
Now, it's also an emotional thing, so it can be hard to abandon ship and get a divorce when it's clear your life plans have utterly diverged; I'm not trying to trivialize that decision. But for the default case of marriage to be “you have understood your mutual obligations and the fact that you are embarking on a mutually navigated life” seems perfectly reasonable to me. As for kids… Kids cost money and time, which our society for better or worse equates with money. So of course kids add to the number.
Engineers who make big bucks and “let” (!?) their spouses stay home or pursue careers as ‘”artists”’ (?!?) are making that choice, either explicitly or by not having the conversation. If you don't steer your life, you let your life happen to you. And if you let your life happen to you, sometimes it will happen poorly. If they are having the conversation, then there's mutual agreement that this is what's best for the family, and no one is letting anyone do anything. It's absurd to talk about anyone “letting” their spouse stay home as if they have some sort of ownership over them, or passing judgement on the value of an artistic career choice from the outside.
Is there a human aspect to this, a fuzziness to it all? Of course. But feeling incensed on behalf of others because their marriages are operating in a way you don't approve of because of how you got burned… I don't know how useful that is.