The proposal becomes more important as many international groups are owned by Russian accounts. While they still have access atm, this could change any moment. I understand that a rouge takeover must be avoided, but there are a number of options:
In case the owner's account has been deleted or not been used for x weeks: 1) the owner might pre-assign an admin to become the next owner automatically if above conditions are met or specify that the group will be closed. 2) a single admin can take ownership. 3) a group of admins can elect the new owner. 4) the account with the oldest membership will be asked if ownership should be transferred to that account. 5) if neither of the above works out, the group will become read-only, later deleted.
3) seems to be the best, but I think only the ones with all permissions should vote (because these were the ones trusted by the owner), or the ones with the most permissions if there aren't any with all permissions.
I did mean to implement all of the above, in that order. So if one condition is not met the next rule matches. But basically you are right. for 3) the admins with the most rights elect the new owner. No 2) was meant "if there is only one single admin, ..."