Ben Torah,
I’m sure it would be accurate to say that your opinion is that the Torah way is to have as many children as is possible, without considering financial issues. I think that is the mainstream yeshivish approach as well. Suppose for a moment that you know well in advance that no child will be allowed to attend yeshiva unless his or her parents pay full tuition every year (which should be the general case, with exceptions being few rather than the norm).
As you say, income doesn’t go up based on the number of children, and once a family has maximized its earning potential (both parents working), homeschooling is not an option.
Is it better that the children should never be born or that the children should be born but attend a school that the parents can afford (i.e. public school)?