Torah learning provides parnossa - sometimes

 Rav Chaim Shmuelevitz (Sichos Mussar 5731 - Bitachon): The Alschich’s students complained that he had told them that one does not need to work but instead should learn full time and have bitachon that G-d would provide all their needs - but it didn’t work. The only one who succeeded by having bitachon was the simple wagon driver. G-d had provided him with a trunk full of gold coins. In contrast the Alschich’s students failed to have their livelihood provided by their attempts at bitachon. The Alschich explained to his students that the approach of relying entirely on bitachon works only for those who have total faith without any doubts at all. Only the simple wagon driver had the pure simple faith needed for the bitachon to work.