She's openly said this on numerous occasions including on a Jonathan Ross interview a few years ago, this isn't new information. I doubt she was 'bankrupt' though. The real money from being a musician comes from touring; the more music you produce, the more hits you potentially have, therefore the more likely people are to come and see you and the more likely they are to pay lots of money to see you live. So the next logical step is to amp up how impressive your actual tour is so that more people want to see you, therefore the ticket prices go up to cover costs and turn a profit... which is all very self explanatory and seeing as popstars don't even get half of the profits of what their music makes, if they're on a major label and regardless of whether they're a writer on their songs or not, it's easy to see how a globally popular artist can have not very much money from the actual sales of their music and why they would choose to invest it all back into their tours so that they can try and make more of a profit for themselves.
