Author here, the project I was referring to is a massive unwieldy Scala project using the Play framework (nothing inherently wrong with those choices). It has 177k LOC. It is a matter of months old. It is complete spaghetti and it's impossible to find what does what without learning IDE tricks.

Guess I could have mentioned that. So actually my experience confirms the observations of Fowler about breaking up existing things rather than starting out with bunch of different services because fads.

That said, I would still start breaking up services that are orthogonal to one another in the same way as one might break up db tables. Iff the interface for writing new services is comprised entirely of a spec for endpoints and their corresponding data schemas. If instead you're thinking of how risky it would be to have a handful of separate services all with their own pile of fragmenting boilerplate to maintain, then yeah, I'd agree a monolith is better still if that's the only option.