The thing that is interesting about points expiring after 24 months of no activity is the fact that the points have a reputation for not expiring. Many people who fly Southwest minimally talk about how the points never expire and my guess is that some will become very disappointed in the future, if the same rules are in place in a couple of years.
It seems that in advertisements for the new rapid rewards 2.0, the mention of points expiring has been done very subtly, almost to give the wrong impression to consumers.