I think this is significant for the unfortunates who use Salesforce software. Companies spend a huge amount and become integrated with the software as a core operating environment. Changing software could be a ruinous expense. On the other hand, such high handed virtue signaling will undoubtedly be a factor for a large number of potential users of Salesforce software in the future. If they can arbitrarily do this to the sellers of one product, what about the sellers of other products that might suddenly become SKW targets? There is some interesting information on Salesforce at the link.
https://www.quora.com/What-percentage-of-big-companies-use-Salesforce-CRM
It's easy to export your data (that you own) from the SFDC platform. It is also easy to set up a competing system and load that data into the new system. It will take some time and there will be some expense (depending on how much of the SFDC tools a customer is using). Retraining people will probably be the biggest expense. Integrations of SFDC tools to other platforms could be the real pain point. And some SFDC tools are hard to replicate on other platforms. It all depends how much of their system you are using.
20% (roughly) use Salesforce. Another 25% (roughly) use SAP, Oracle and Microsoft, in that order.
Sounds like a great opportunity for SAP, Oracle and Microsoft.