It looks like the membership fee thing isn't a pay-wall. From lower down the page: "Exclusive benefits for participating organizations include: Participation

It looks like the membership fee thing isn't a pay-wall. From lower down the page: "Exclusive benefits for participating organizations include: Participation in arXiv's ongoing governance through the Member Advisory Board, which provides input for project prioritization, new service offerings, financial planning, use of discretionary funds, future technical developments, and policy decisions; Access to enhanced institutional use statistics; Public acknowledgement of members' role in financial support."