Are you telling me that out of the supposedly 1.1M managers and given the 1:2 distribution of teams for each lower level that you could not fill 10% or 25% of the already selected teams to have covered all the cases? Why do you need 80% of clubs in 5th or 6th division to have youth squad, when 1st league divisions or top 1000 vifa rank is only 0, 001% of game population?
You are starting from a false premise that the distribution of teams is uniform throughout the divisions which is completely false in a pyramidal system. I would bet you that youth squad distribution is around 60% of teams in 5/6th divisions, 20% of 4th, 10% in 3rd div and 10% or less in 2nd and 1st division.
When it should have been equal as percentage but close to 100% in 1-3 divisions, 50% in 3rd 25%in 4th and some 12,5% of teams in 5th and lower to maintain an even distribution in numbers.
You are starting from a false premise that the distribution of teams is uniform throughout the divisions which is completely false in a pyramidal system. I would bet you that youth squad distribution is around 60% of teams in 5/6th divisions, 20% of 4th, 10% in 3rd div and 10% or less in 2nd and 1st division.
When it should have been equal as percentage but close to 100% in 1-3 divisions, 50% in 3rd 25%in 4th and some 12,5% of teams in 5th and lower to maintain an even distribution in numbers.