To the best of my knowledge, save for the nursery, the programs are focused on discipeling the youngsters at an age-appropriate level. We had one sister who pastored the 5 to 7-year-old S/S class for over 30 years. I worked in Junior Church and can say the attendees got Bible Truth at a level they could understand. Mind you at around 11 years they moved into the main service.
What prevents a teacher from teaching the children about Jesus - on a level they can understand. Sure, there may be toys - but keep in mind that young children have a short attention span. Even when the children are playing - they can be singing "Jesus Loves Me"