At least in our case problem can be solved by re-encryption. Yes, we have to keep up to date with developments before everything is completely broken, but it is not bad as discovering a bridge needs to be rebuilt. Speaking of which, it is common to have to retrofit for earthquakes which probably wasn’t the rule when they built the original bridge
That depends on your threat model. A patient attacker can store all of your encrypted messages till some future point where decryption is economically feasible. Since they already have the weakly encrypted data, encrypting it again doesn't solve anything.
