Decorating isn’t for the baby. It’s for you! I’m sure you think all those toys are stimulating your baby but really they’re just creating more product dependency. You don’t need all those things! What the baby needs more than anything is stimulating interaction with parents!
I know dirt-poor people who have brilliant children. I went to college with a 12-year-old classmate from such a family. His genius had nothing to do with brightly colored toys nor bouncy twirly whatevers.