[sofixa]

100k monthly active users can result in wildly different numbers of queries/requests/operations depending on what you're doing.

100k MAU for a static blog and 100k MAU for an online game simulating a real world economy will have vastly different usage patterns of the underlying databases/message queues/etc.

> With that in mind why spend so much resources on complexity where the only benefits are to the engineers that get to add another buzz word to their resume?

It's not the only benefits, it's making things potentially easier down the line; more often than not it can be premature optimisation (preparing for a future that never comes), but there are also plenty of examples of companies outgrowing their initial infrastructure and having to spend lots of time on rearchitecting everything. A lot of that time can be saved by thinking a little bit beforehand and making things theoretically scalable.