It is, but the nature of the application demands that a write query is not considered done until it is guranteed persisted on the disk, and the same data is rarely queried often enough to warrant a dedicated cache layer. The data that is queried often is so far handled by SQL Servers buildin caching gracefully.

That isn't the same as we couldn't get some benefit, because we could especially as the userbase scales. But so far we haven't had to scale to the point where it's worth the added complexity to persuit. One can only look forward to the day it is.