No one is to blame for Pia's departure. She just didn't inspire enough voters to stay in. It is that simple. There are lots of reasons why a singer fails to get enough votes, not just one.
The publicity her departure is getting is going to help her.
Stephen said he could name 5 top recording artists who had pitch problems so being a good singer is only part of the package of a star. There are other early boots who are a success, Jennifer Hudson, Chris Daughtry, Kelly Pickler to name three. This show is a huge stepping stone for careers no matter where you place.