Dear Gadol,
There are thousands of frum couples and thousands of life stories. It’s a series of binary choices. The real open-ended question is what is sufficient funds.
I disagree with your assumption. Kollel is mostly a life stage and not a life-long plan. Almost everyone in kollel [I am not discussing Israel. Totally different.] now, will have left to join the workforce, when their kids are in kollel.
And the kollel wives all have some form of employment at some point. I have never heard of any kollel wife that never worked in the modern day [Again, not counting Israel].