영어 문장에서 to earn more money의 품사가 궁금해요

“The only solution to these problems is thought to earn more money to buy more comfort.”에서 to earn more money는 어떤 역할인가요?
이 문장을 수동태로 바꾸기 전 문장이 “People think that the only solution to these problems is to earn more money to buy more comfort.”가 맞는지도 궁금해요.