Individuals and organisations aren’t guaranteed continued employment/funding—it’s conditional on performance.
It’s conditional on the appearance of performance, which is something else entirely.
For example, academics making a discovery are incentivised to slowly release the results over multiple papers, where it would clearly be much better for the community if the results to be published quickly in a single paper. However, in the first case, there is more appearance of performance.
I think that would threaten to destroy useful projects. Likewise, it would mean that experienced, valuable staff couldn’t continue at their org.
I think this argument would have more merit if there weren’t already many organisations that do have term limits and have not been destroyed. In many countries, despite having regular performance reviews (elections), even the highest executive positions are subject to term limits.
There are certainly good things you can do where you can’t measure the outcomes to work out how effective these are. As a prior, I would say that the fact that an intervention is non-measurable should count against it. If non-measurable effects are regularly accepted, then you will see a lot of organisations claiming non-measurable benefits and there will be no way to reasonably evaluate which ones are providing legitimate value and which ones aren’t.
In addition, even if you don’t know if your actions will be effective, you should be able to finish doing the actions at some point.