"What is the philosophy of the web community? Just add more cores!" -- I think this is mainly because of the commoditization of computing resources. It is a lot cheaper and has a faster return on investment to add more machines, each of them running slow applications, than to spinning up a new team of engineers to spend valuable manhours to tweak the application so that it only runs marginally faster on a single machine. Some shops are always forced to iterate fast and ship new features. They worry about getting the thing out the door first before making it scale.