Sure it exists in theory but I can asure you that in practice it's as rare as hen's teeth.
As for your increase in income due to child benefit and lower taxes your argument is seriously flawed there. Do you think that children are free? If you assume that you pay 70chf for health insurance for a child you've already lost a third of the child allowance benefit and that's without feeding and clothing them. Add to that the need for a bigger flat and therefore increased rent and I think you will find that having children has a negative rather than positive affect on your income.
A couple with no children don't need a three bedroomed flat, a one bedroom is fine so the savings on rent alone would easily make up for the 'supposed' advantage having a couple of kids would bring.
You do know what the term "average" refers to, right? It is an average of e veryone with a job and income, skilled or unskilled. And do you seriously think an unskilled worker would earn 7k+/month in Switzerland?
85k p.a. and some people actually think you bascially need to line up at the freaking soup kitchen Zero sense of reality.
It is fairly expensive here. To give an example at the lower end. I'm on 60k p.a and am saving ~10k pa, however this is living in a share house as a single, with no regular meals out, and making my own lunches. It does involve going travelling on a weekend about once or twice a month (flights and Airbnb).
In Lausanne and around there is some subsided housing.
I remember my shock when I saw ads in canton GE ( not in Geneva city, mind you) for a subsided apt for a family of 2+1 with cut-off threshold about 90-95k gross.
With 3 children and more, SKOS estimates per-child direct cost at about CHF500 (food, housing etc) plus a cost of lost income (let me skip it).
Arguably child benefit plus lower tax accounts for part of this.
As I have to house, feed, clothe, home-school in my language, haul, insure etc a family of the size in the 95th percentile, I know all this first hand.
But that wasn't my point. My point was that a 85k in Lausanne is effectively not much more money that a worker family 2+2 would get.
Whether this is enough/much - I don't want to discuss it.
Recently I've heard in RTS La Premiere, "On en parle" about discrimination against foreign renters - they've asked a African-accent person and a Swiss to call and ask about the same apts dozens of agencies and and in many of them the response to the immigrant was that the apt is already gone while they said to the other the opposite.
An immigrant is not on equal footing and what might be enough for a local might be too little for a newcomer - the playing field is titled against him.