I have done exactly this in the past. I made a webpage explaining the benefits of the enterprise license (individual contracts, assistance with vendor security

I have done exactly this in the past. I made a webpage explaining the benefits of the enterprise license (individual contracts, assistance with vendor security assessments, etc.), and asked customers politely if they wanted to upgrade to an enterprise license. Not a single company (out of maybe a dozen companies that I made the offer to) actually took me up on my offer. When they find out that the vendor assessment would cost them money, they suddenly find a way to use my software without the vendor assessment.