Toddler needs top four teeth removed

The enamel is completely gone on his top right tooth and is spreading to the other three surrounding teeth. The dentist said to pull all four I was hoping they would cap them. Yes we brush a couple times a day and Ive limited sugary foods juices etc. I’m really just upset and don’t know why even capping isn’t a possibility (saw a different dentist a few months back and had him on a wait and see approach clearly that was not working so I took him to a different dentist) and we jumped straight to extraction he just turned two. He got four teeth at 3 months old and all came in very quickly after that. Has anyone dealt with anything similar? Just need advice