For quite some reasons:

1. The men are uneducated. Since one man might have made N100M without going to school 100 years ago, most refuse to go to school and port to business after primary school. They feel too uneducated to talk to their wives (who are 99% often educated). Most have age gaps of 9y-10y with the wives and many married them as trophy wives.
So they leave the wives to run the house.
These wives want to create impression of "my new class" so they seek for candidates to worship and show them that class. Ideal unfortunates are u-12s whom they won't feel threatened by.

2. Igbos love of those with money. They will willingly give out the children to stay with and "help" this big man/woman. Worse, they won't even visit. This is the main issue to talk about. Many uneducated feel conquered by the one with money.

2. Leaving people with u-13s that are not their own. They feel they can do you something and nothing will happen. Hence all the hell you read on media.

Solutions

1. Don't marry uneducated people. The disadvantages outweigh the "advantages" 70:1. Many are not qualified to run homes. They know nothing outside 'trade money' and are very self-centered. (Did nothing about Awkuzu SARS till it came to notice of educated youths). Many even avoid anything Church outside the normal Sunday/Sunday (if at all) because even the Church requires some education.

2. Go to school. Find a way to make money with school or copy from Americans, Europeans, Chinese.

3. Mandate Secondary School completion for everyone.

4. Don't give out your child outside your home for anything, especially before 16. Don't value any money not your own. If you really value it, seek to make it yourself.

Igbo people una too do