> If sharing won't generate enough revenue to pay for the cost, why would you?

Any one-time cost can be amortized in time by recurring revenues, after which you're left with pure profit.

Technical work (manage your reader's cookie and policy preferences etc) is a one-time cost. Revenue from EU readers is an ongoing benefit. Hence, as long as EU income is greater than its traffic serving costs, you're bound to come ahead after some amortization time.