I guess in the abstract that seems plausible to me. There may be questions that prime ministers and senior cabinet ministers get involved in, questions of the highest order, such as acts of war and things like that. It may well be that in the abstract, some of those are absolutely essential, even if there's a conflict of interest. Then you'd start to look for mitigating strategies. Certainly, though, I would think the list would be relatively short.
On August 10th, 2020. See this statement in context.