And 365 days probably aligns with 100% of scenarios. It doesn't mean it's a good idea, because the longer the delay is the more downsides you also get.

Blocking a maintainer from pushing updates for a full month after changing their e-mail would be obviously absurd. So Github would have to add a way of enabling maintainers to super-uper-duper confirm the change and cut the delay short. Which is likely not currently possible, hence starting with a shorter delay.