But does it not make you more vulnerable to competitors? Losing one of your few big customers will hurt regardless, but it likely hurts less if you have a pool of SMBs to act as a buffer.
A segment of a customer base is hardly a buffer, if you underserve them they will leave, and you will have wasted effort making an inclusive sales and support process to them.
This shows up especially in the context of hiring: for a generation, there have been a ton of people who learn VMware at businesses of all sizes and your large shop can reliably hire them. Shutting down smaller sales affects that directly and because the smaller places are going to do something else it means that the people who move up to a bigger place are going to have direct firsthand experience contradicting what the VMware sales people are saying about how risky it is not to use their software.