Why do fatwas prohibit most things without offering solutions? Is this due to the inability of scholars and their lack of diligence in addressing contemporary issues? Is it permissible to criticize them given that they are not infallible? And what is the significance of their saying "And Allah knows best" at the conclusion of a fatwa?

Muslim scholars have exerted great effort in issuing well-founded Sharia rulings (fatwas). The basis for prohibition among them is what is indicated by Sharia evidence, and the default rule for things is permissibility unless there is evidence of their prohibition. The questioner has the right to ask the mufti for the evidence. Usury (riba) is forbidden by consensus in all monotheistic religions due to its exploitation and accumulation of wealth, and Islam has provided permissible alternatives for it. It is permissible to advise scholars and rulers and correct their mistakes, as advice is obligatory, and no one is infallible after the prophets. Concluding a fatwa with "And Allah knows best" is a form of deference to Allah, attributing perfect knowledge solely to Him.