What is the fine-grained topic of the following text: Adele and Ed Sheeran are prospering (they are numbers one and two in the latest Sunday Times list of the UK’s richest musicians under 30), while the group-oriented genres of rock and indie music are in decline (the Arctic Monkeys have recently been described as being ‘virtually the last indie band standing’). Only return the topic.
The financial success of Adele and Ed Sheeran compared to the decline of rock and indie music genres.