I think there is a bit more than just one thing missing there. It looks like 3 or 4 loose thoughts poorly put together on single sheet of paper as a snake oil r

I think there is a bit more than just one thing missing there. It looks like 3 or 4 loose thoughts poorly put together on single sheet of paper as a snake oil remedy to all your aches. You don't need to strech your imagination too much to come up with counter examples which would make authors unfonfortable. Ie one of the most performant architectures are used in financial exchanges, they don't look anything like whatever this web page describes. Pretty much nothing there applies to people doing machine learning, working on games, internal services, prototyping and more – they can and often are distrubuted but not in the narrowed view of the world presented there. Some insights like "message-driven as opposed to event-driven" make you question author's knowledge on the subject of distributed systems. Probably better to ignore and base yourself on more credible sources.