But nothing on OSM is "up-to-the-minute". Many OSM data consumers are months behind OSM discourages putting anything temporary on the map. While I do add OSM business hours including public holidays a lot, this isn't always possible when businesses don't have pre-planned holiday schedules.

The spec is very detailed and allows a lot of granularity. Unfortunately, real businesses often don't have set holiday schedules but rather play it by ear each year. OSM has no way to add "this business will be closed on these holidays this year, next year might be different". When lots of businesses introduced modified hours during the Covid lockdowns, there was no concept of temporary opening hours so a "opening_hours:covid19" was introduced. Older data consumers simply ignored that tag. More generally OSM is only for data that is (mostly) permanent. Adding "this business will be closed for Christmas this year" is not OSM data. "This business is closed on Christmas" can be added on OSM. But many businesses don't plan that far ahead as to have set announced holiday hours that can be written in the OSM opening_hours syntax.

Maybe my business is a corner case which avoids the automation - I am open usually 9-5ish, but can be open anytime if a customer rings the well and waits for someone to get out of bed.

Google has an actual human call every 2-3 months, who usually just asks the opening hours, confirms one other detail (usually the website) and then says goodbye.

A local restaurant near me in Australia said they had a Google employee ring asking to confirm their opening times.