What makes you think that it was? Sufism was incredibly popular long before the rise of the Ottomans. It was and is extensively practiced, for example, in the Indian subcontinent and in South East Asia. Sufism was embraced by the Ottomans but I'm not sure I would describe it as being quantifiably stronger than in other places. I'm certainly not familiar with any data to suggest that it may have been. It was embraced by the state, but that was certainly true elsewhere as well.