What's conspicuously missing is the plot of performance when you do have a well tuned queue in front of the service. Yes, having a queue becomes less important the more backend servers you have, but here even with 10 servers the plot shows your latency remains >25% worse than it would be with a queue. Also missing is discussion of how the variance in processing times affects you when you rely on load balancing alone.
> What's conspicuously missing is the plot of performance when you do have a well tuned queue in front of the service.
As in between the service and the load balancer? There's already an infinite queue in the load balancer. You can try that out on https://stability-sim.systems/ to see the effect, but the short version is that (in this model) it makes things worse.
If you're saying that the queue in the load balancer should be limited in size to reduce tail latency, then I agree.