My 3 yo keep getting worse

I have a 3 year old and I brush her teeth consistently. As you can see she already has caps and now her tooth and the same one on the other side is just like it.. I take her to dentist and they just say brush brush brush and I do guys. Idk what else to do is it possible she could just have bad teeth period. Like I literally brush 3x a day at she gets nothing but water after brushing at night like what do I need to do I feel like a failure