The point should be, "how to we forestall demographic collapse?" Well, one way was immigration, but they're doing the opposite of that, so better make it easy to have lots of kids!
How so? The net migration graph here shows very high levels of immigration: https://www.gov.uk/government/publications/migration-advisor...
Recently after dropping no-fault divorce, more onerous child support laws, "red flag" and other temporary protection orders that can be obtained on little more than a mere one-sided claim (David Letterman famously had one against him for "sending coded [abusive] messages through the television"), alimony that relies on old timey presumptions a divorced partner can't work, etc, the calculus is looking ever more desperate.
Nowadays marriage still has most the downsides, but the upsides are looking less and less. And even more, the contract can totally change out from under you, you are basically agreeing to a vague contract that society can arbitrarily change at any moment and all the meanwhile scream "you agreed to this" no matter that it was unilaterally changed by a 3rd party to the contract and the playout of the actual terms of the contract hidden within places like family court where it's literally illegal to release the proceedings that allow one to make a rational decision upon ("think of the privacy of the children").
Not causally it isn’t.
I disagree with this entire social project, babies aren’t interchangeable and I don’t want to encourage more children from people whose primary blocker was child support payments. Need to encourage people who are doing well supporting themselves to have more children rather than squeezing out the tenth from two-timing Jimmy.
>I don’t want to encourage more children from people whose primary blocker was child support payments
A prime reason why I didn't have kids in my 20s was because I could afford the kids in marriage, but couldn't afford to spend 20% (more like 30% post tax) on child support, as I had calculated it out. And knowing divorce is always possible, not willing to risk that. The actual cost of my kid is like 10% of my income, but because I'm married I'm not forced to spend closer to 30% as a transfer payment with no check it actually goes to the child. Without poorly thought out child support laws I'd have had kids sooner, and possibly more, and the kids would likely have been better off because when I was younger I had more energy and better genetic material to produce them.
I would even assert the people thinking ahead of time about child support actually calculated in a way that achieves roughly enough to take kids out of poverty, rather than basically a % of income, are exactly the type of people that should be parents. Under the current system child support can be next to nil, or extremely high if you're high income, rather than revolving around ensuring it is actually a number and check and balance to ensure the payment and spending is to bring kids out of poverty. The current system has less child support for poverty-born children but higher for wealthy-born children, meaning the incentives are precisely backwards from incentivizing children born into higher income marriages and the CS incentives higher for higher-income families to divorce and fall back into the lower-fertility unmarried bucket.
I struggle to find any data that shows positive (increasing) correlation between modern family law and marriage rates, so I'm curious where you got your conclusion from that those things are improving women's proclivity to marry.
No idea how it would all add up, but its not obviously true.