That is actually true in the US as well with NIH funded research [1] (the majority of biomedical research). HOWEVER, the research need only be opened after a time-embargo (generally a year). Additionally larger universities like the University of California system also 'require' open access publication [2] - however waivers to that requirement are often sought and easily granted.

In both cases, the policies (NIH in 2009, UC system in 2013) were shots across the bows of the large publishers, and permit a gradual easing of the culture without just blowing it up. So long as the eventual goal of all open-access is met in a relatively timely fashion, I think the strategy of slowly cinching down the rule is a reasonable compromise.

[1] https://publicaccess.nih.gov/policy.htm

[2] https://osc.universityofcalifornia.edu/open-access-policy/in...

The EU as a whole is also moving towards this: https://ec.europa.eu/programmes/horizon2020/sites/horizon202...