Just a thought... opening hours can usually be scraped from their website (totally unfounded guess: that's how Google does it), so what seems to be missing here is a free tool -- and probably a free central database of pre-scraped data -- to collect this information for others to use together with OSM data. The process will be a bit different from OSM because data is scraped, not edited.

Edit: To add, if such a tool needs site-specific configuration to work, then that configuration could again be community-edited in a style similar to OSM data.