Not when you're looking at high utilization, as presented in the example in the article. For that particular case (a M/M/1 queue with arrival rate of 5.8 custo

Not when you're looking at high utilization, as presented in the example in the article. For that particular case (a M/M/1 queue with arrival rate of 5.8 customers per hour and a service rate of 6 per hour), even your median response time is 3.5 hours. Unbounded FIFOs are _really_ bad once you get to high utilization.