I hope you understand what I have in mind: people often write there hardware wallets mnemonic on paper and it could be compromised without they know it, adding a relative time lock will alow owner to secure there funds to another secure place once it has been compromised.
Of course I suppose it have to be part of hardfork since all the network has to implement it to be functional.
Thanks for reading, hope it wasn't so silly idea

I don't think the idea is silly. The thing is, you are suggesting people to store 2 seeds instead of one with this failover address.
If people lack responsibility to store one seed, they will just store 2 seeds together.
You can split your seed, use a mnemonic phrase, etc to increase security.