On the contrary, scaling and parallelism are much easier on a multicore machine (possibly with a NIC queue per socket) because most nontrivial workloads are ult

On the contrary, scaling and parallelism are much easier on a multicore machine (possibly with a NIC queue per socket) because most nontrivial workloads are ultimately communication bound. Single load balancers can handle most real sites' traffic and direct them to different cores, and for those concerned about (for example) DDOS attempts, services like Cloudflare will allow you to combine IP anycast with a reverse proxy to avoid this problem far from your machine. For a large percentage of use cases, the only reason to have multiple machines at all is for fault tolerance, and for most of the others, it's just not being able to fit all your data in memory (increasingly rare). That said, modern networking has gotten good enough that in a really high-end datacenter you can sometimes still get increased performance out of the network (using RDMA, etc.), but you have to really work hard for it (usually bypassing the OS networking stack).