15 years for the first 100 AU, and we’d be getting data every day for that 15 years.
Your reasoning sounds oddly like the liberals who opposed the Keystone pipeline (and before that North Slope drilling) because ‘we wouldn’t see a drop of oil for 5 years’.
We can be at 1000 AU in less time than it took to build a medieval Cathedral. Did that delay make their efforts unworthy?
150 years from launch, the probe would have been non-functional (and/or out of comm range) for over a century.