You still think your way is the only way and the best way?
My point is that you CAN have a VERY strong bond without taking children away from their own personal lives and temporarily incorporating them into yours. Spending a week or more sleeping over is NOT necessary for building a strong relationship.
I am sure that you can have a very strong bond without taking children into your home. I am also sure you can have a stronger bond if you do. The child is in your custody for that period of time. You are a surrogate parent. The child relies on you for everything from food to providing comfort for a scraped knee. The longer the child is with you the more instances of surrogate parenting are required like correcting bad behavior, dealing with a frightening situation, or just answering questions about how things work. The child learns they can rely on you through good and bad. The more you have of both the stronger the bond.
Let's consider another example:
Grandparents A live close by. To help cut down on the cost of daycare they agree to take the child every day after school and keep them until the first parent gets home 3+ hours later. In addition, Grandparents A are around for ball games, general get-togethers, and holidays.
Grandparents B live 2 states away. They are loving grandparents and they make the trip to see the child 3-4 times a year and especially on holidays and birthdays. In addition, parents and child go to visit grandparents B at least 1 time a year themselves.
Do you really think grandparents B could possible have the same bond with the child as grandparents A who serve as surrogate parents and see the child practically nonstop?
More time = stronger bond. It really is a simple concept.