One aspect of ads you're ignoring is how they spread the cost of using a product: whereas charging a fee impacts all users equally, ads will generally impact us

One aspect of ads you're ignoring is how they spread the cost of using a product: whereas charging a fee impacts all users equally, ads will generally impact users relative to their income / spending habits. It strikes me that for Wikipedia, that is more compatible with their objectives than a set per-user fee. I'm haven't thought of many reasons to like ads over they years, but this is one.