The challenge is that all budgets are locked down and the business owner is unwilling to take money from their marketing budget (or any other budget) to put towards analytics.
My 'growth marketing' approach to this question would be to research and write a sold content piece answering this ROI question with best practice and case studies.
That piece can then be both shared with prospects as a way to open up a discussion, and used as sponsored content on LinkedIn to better qualify new prospects.
In other words (taking a leaf out of James Clear's 'Atomic Habits' focus on getting the process right) demonstrate you know why analytics are so valuable to a business first, then share that with clients to start a better sales conversation.
I used a similar approach in a recent B2B marketing role where I convinced a member of our field sales team to collect data from our existing client on the ROI of using our software, and turned that into content that both drove upsell and helped engage new prospects via LinkedIn.
Happy to chat more if it would be helpful!