If you are offended, asking “What have I done wrong?”, I understand, however, quite frankly, you could have done better. Everyone has their first time being a parent, just like the first time you learn to walk, to ride a bike, failure is inevitable.
It is true that you have invested a tremendous amount of time, work and devotion, but there is one thing you couldn’t avoid: inertia. The stroller surely wasn’t designed for the baby, it was for the parents who didn’t want to carry their own baby. The same parents that years later would complain about their child’s lack of exercise. Have you ever seen a toddler gluing to the ipad because the parents are fed up with his crying? The same parents would later complain about the kid’s gaming addiction.