he pretty explicitly states that AES 128 is not in any imminent danger and mandating a switch to 256 would distract from the actual thing he thinks needs to happen.
Then again, something something md5. 'Just replace those bytes with sha256()' is apparently also hard. But it's a lot easier than digging into different scenarios under which md5 might still be fine and accepting that use-case, even if only for new deployments
There's a whole lot of cases where the tokens are temporary in nature with an easy cut-over, either dropping old entries or re-encrypting while people are not at work. We tend to think of big commerce like amazon or google that need 24/7 uptime, but most individual systems are not of that scale
In most other cases you increment the version number for the new data format and copy-paste the (d)e(n)cryption code for each branch of the if statement, substituting 128 for 256. That's still a trivial change to substitute one algorithm for another
Only if there exists no upgrade path in the first place, you have a big problem upgrading the rest of your cryptography anyway and here it's worth evaluating per-case whether the situation is considered vulnerable before doing a backwards-incompatible change. Just like how people are (still) dealing with md5
You can’t just throw “Grover’s algorithm is difficult to parallelize” etc. It’s not same as implementation, especially when it gets to quantum computers. It’s very specialized.