I believe you may have failed to consider the important role played by reliability. X cannot always be done reliably - it usually relies on timing. Y, as we've

I believe you may have failed to consider the important role played by reliability. X cannot always be done reliably - it usually relies on timing. Y, as we've seen, can be done with some degree of reliability. Combining them, in the wished-for world, creates a more reliable exploit environment because the spoofed records will not expire. The result is more attacks that persist longer and are more likely to reach their targets. Such a world is certain to not be better than this one and likely to be worse.