a) Engineering: Nobody will rewrite 20 year old views just to improve the UX. In many cases, nobody even dares to touch the 20 years old spaghetti code.
b) Sales: The buyer is not the user. The buyer (playing golf with a sales rep) doesn't give a damn about the actual productivity of what he is buying.
c) Management: There is a solid economical rationale in not giving a fcuk about UX. Over the years, SAP outcompeted and absorbed many competitors that were more interested in UX than golf. Golf won every single time. Nobody at the top understands or cares about UX because it does not bring more revenue, it is a cost.
Source: I am an ex SAP.