I interpret this as meaning that this is only a challenge for the kind of over-scale systems that only a handful of companies have.
You could be a pretty significant online retailer (Asos, say), run everything on a few instances of a monolith, and have all your information in easily interpretable log files, without needing to reach for distributed tracing tools.
You could be a pretty significant online retailer (Asos, say), run everything on a few instances of a monolith, and have all your information in easily interpretable log files, without needing to reach for distributed tracing tools.