Six services that must be released together, share a database and call each other synchronously have every cost of distribution and none of the benefit. It is the default outcome of splitting by layer rather than by capability.
// split by layer: every feature crosses all three
// api-service → business-service → data-service
// split by capability: a feature lives in one
// catalogue | ordering | fulfilmentThe symptom is a release checklist with an order in it. The cause is usually that the split followed the code structure that already existed, because that is where the seams looked obvious — and layers are seams between technical concerns rather than between reasons to change. Merging back is a legitimate fix and is almost never proposed.