While the reasons for stakeholders being resistant on that feature remain unclear in your description (probably for a good reason) the most obvious choices are the following:
- Associate the financial benefit to that feature. E.g. by sales committing leads/deals or $$ market potential
- Skip sales and run feature voting directly with users/customers. Only IDed users can vote, this builds an audience for that feature which can be addressed. With that audience it will be easier to understand the benefit of the feature and get stakeholders involved.