[evincarofautumn]

Caching can be critical if the volume is high enough. There are physical limitations of computing appliances that make sites like Google or Facebook actually impossible to run without extensive caching and indexing layers, not just prohibitively expensive.

[scrollaway]

I thought that was obvious. OP was making a point about things running without cache at the cost of increased load... I'm sure Google Search couldn't reliably achieve that right now, but we were not talking about Google Search.

[evincarofautumn]

Right. I figured I wasn’t telling you anything new, but thought it worth making explicit for the benefit of others.