I am not sure there is a single solution to this that would work across all industries, as the impact of the bus factor can be quite different depending on the business.

Software as a service requires that someone else has access to servers, repos, and the required technical expertise to keep it running. An accounting business or lawyer would require a roadmap to transition all their files and documents.

Maybe the generalized solution is like ISO 9000 or XBRL for transition planning along with a centralized depository with all the information required for a transition. The depository releases the plan upon the receipt of a death certificate or a board motion or just a lack of contact with the founder over a certain period.