The COS can do a better/smarter fundraising effort than the one they are planning...

The proposed COS fees for preprint services are an invitation to failure.

They are directed at the wrong agents, and create perverse incentives.

If the COS wants to get money back from the people who use these services, they should be asking authors who have their content on the service, not the managers/editors who are already volunteering their time to shepherd the content into the service.

Any reasonable cost-recovery effort would support and applaud preprint efforts that manage to gain the most use. Instead, this would only lead to higher fees charged to people who are already working for free.

What happens when a preprint service cannot pay the fee? Didn’t the COS sign up to be the host of this content in perpetuity (whatever that means)?

Wikipedia does not ask its editors to pay for the service, it asks its users. The editor/governance volunteers for preprint services are the last people who should be tasked to come up with money to support these.