The business case is the easy part, the quagmire is in getting the different teams to agree who should support the business case, why it's more important than the business cases they wanted to spend cycles on instead, and how much of the pie supporting it takes on the budget side. Less so when the place is small enough everyone knows everyone's name, more so when it's large enough they really don't care what your business case is much even though it'd be 10x easier to support from their side instead of another.