I've never said I'm entitled to some answer
You expressed being disconcerted over not getting responses quickly. You shouldn't be.
I will comment that gradual decay is unimplementable in practice as far as I know. No one has proposed a method to implement it practically and the only method I can think of would be enormously complicated (the latter being a property of things that are a very, very bad idea to code into a consensus system).
Simple expiration is feasible and I am in favor of it. I would base it on the account being completely inactive for some period, indicating possible loss of key.
Maybe you're right! I'm not perfect. Far from it.
Same here! Also inactivity in regard to active key.
Yes active or owner key should should demonstrate some usage otherwise it may be impossible to change witness votes and they should eventually expire.