When it comes to contingency planning, it's important to create separate plans for each product or service you offer. This is because the risks associated with each product or service may differ. To create effective contingencies, you need to address the specific risks associated with each product or service, rather than focusing on the vendor as a whole.
For instance, Microsoft offers hundreds of products and services. While it might be easy to replace Microsoft Office with Google Workspace, switching from Microsoft Azure for cloud services requires more detailed contingency planning.
Although it's true that vendors can suddenly go out of business or become less desirable due to increased risk or poor performance, it's more likely that a vendor will discontinue a specific product or service instead of shutting down altogether. By planning for contingencies at the product or service level, you can ensure that you have a detailed plan and the confidence to move forward with contingencies, regardless of the vendor's overall situation.
I hope this information is helpful, but I would love to also hear from other members.