The global-tally objective can be achieved by applying the freshness requirement only to z-addresses, and keeping t-addresses exempt because they can be trivially tallied. Then, “hibernation” and unlimited offline storage can be achieved simply by transferring the funds into a t-address.
This doesn’t achieve the other goal, of requiring fresh software. But having funds stored in t-addresses significantly reduces the pertinent attack surface and susceptibility to incompatible upgrades. For example, decade-old funds held in a z-address may be unspendable if the zkSNARK scheme has been replaced meanwhile, but it’s hard to imagine a fork that would make plain transparent funds unspendable.