Originally Posted by GeneralMental:
“Put it like this: why bother doing a world tour when you can do film roles that pay ten times as much and require 10% of the effort.”
True. I think that before she got the job on American Idol, she didn't see her music career as her focus. It wasn't exactly a massive success, her albums underperformed while her singles did well. So a worldwide tour wouldn't have been too high on the list for her. But if she has a greatest hits coming soon it makes perfect sense to do one!
One note though, is she
that big worldwide?

I thought her music career was mainly successful in America, and partly in the UK. She has fans, yes, but I think most of them would be casual fans who wouldn't be too crazy about getting tickets. Selling out venues worldwide could be a challenge.