She is like an ordinary person you see everyday. She got lucky with a catchy song that caught on and became huge.

All of this

She was ahead of her time. Too iconic and legendary.

If you are releasing generic pop music then your songs need to be hella catchy and she failed to do so after call me maybe, that song is a POP.

Call Me Maybe was far too big for her to handle at that point in her career. The song was everywhere and it got to the stage where it annoyed more people than it didn't. People probably just didn't want to listen to anything she released after it because they've heard enough of her to last them a lifetime.

Her second single was not good enough.

She's still coming