They've been doing subscriptions for more than 1 page at a time for at least 6–7 years, and it’s been working out okay. Do you have a reason beyond the anecdotal that makes you think it’s one of the worst ways to monetize?

FWIW, I think giving everyone access to the full content but a page at a time while letting subscribers see a nicely formatted PDF is a perfectly reasonable perk. Cutting the reviews in half and only letting non-subscribers see the first half seems like a terrible idea to me.