You have absolutely no idea how much she made, nor what are her spending habits. The more money you have the more you spend on shit you really don't need but buy on a whim. There are plenty of stories of people who won huge lotteries and within a year or two were bankrupt lol
There are a few reasons she might have come back for:
1) missed the attention and well might make some good bucks while she's at it
2) the bank account got thinner and thinner so time to make it fat again
3) split with her bf/fiancee and decided to come back for attention while she's single (that would be great tbh, cus maybe then she would accept a Brazzers contract or some other company, so we would get proper shot porn with good angles and whatnot)
4) was gone for a year or so, pooped a baby, got back to shape, came back to make more money
Generally, none of us has any idea what is her financial situation nor why she exactly came back for. But we can assume that making money is definitely a factor in it.