I agree it is higher risk having only one wage earner, but sometimes it makes financial sense, and it definitely can have developmental benefits (e.g. 1:1 ratio instead of 1:6 or 1:8).
I would suggest that if anyone does do stay-at-home, that when the kid has all of their shots, you send them to a play group or preschool so they can learn to socialize.
PS - We also had kids fairly late, so got all our student loans paid off, and saved a little money which has helped as a buffer.
Wage growth compounds, so you have to take that into consideration. If your employer has a modest retirement contribution that you can take advantage of, that alone makes employment "worth it" from a purely financial prescriptive.
https://www.cbsnews.com/amp/news/staying-home-to-parent-can-...
So even if matching retirement contributions technically tipped the scales, it would still be nowhere close to worth while.
But it also probably means living a less robust lifestyle to keep expenses reasonable for a one-income household. The trap many DINKs fall into (not accusing you, just riffing on my observations) is living a lifestyle that's on the edge of affordability for two earners, and thus feeling like they HAVE to have two earners indefinitely.
I know a few couples who didn't take the loss of 1 income into account and they are really struggling.