Babies have costs, kids not so much. All the hospital charges from minute 1 of birth to discharge. The 72 shots they get, the 100 urgent care visits the mom insists on every time the baby has a runny nose. Auditory and visual testing.
But yea, after about 2yrs old they are practically maintenance free.
Car insurance rates do increase even if you have a perfect driving record. Rates are based on groups. The 30% increase in distracted driving injuries in the the past year is about to cause a nationwide bump (if it has t already).