A team can look fast. Pull requests land, branches move, the board is full of green. The release is still late, because each person is building against a private diagram of the system. Nobody is lying. They just never wrote the diagram down.
Speed at the wrong layerLink to this heading
Coding is the visible part, so it gets the credit and the blame. A lot of the delay sits earlier. What is the boundary of this service? Which data is allowed to be stale? What happens when the request is sent twice? If those answers live in three heads, the code will express three systems, and the review will be a negotiation instead of a check.
Planning is a shared pictureLink to this heading
System design, in the useful sense, is not a poster of boxes. It is a few decisions written where the next person can disagree before they have spent a week implementing the disagreement. Planning is how you notice that the "small" feature crosses a boundary you do not want to cross yet.
Microservices do not fix this. They multiply it. Each new service is another place for two people to be silently correct about different things. Technical debt shows up later as the cost of those silent disagreements.
Release is a team eventLink to this heading
Code review catches the disagreements that made it into the diff. It cannot cheaply catch the ones that were never discussed. Spend the uncomfortable hour before the coding starts. The release gets shorter, not because anyone typed faster, but because fewer people have to undo a confident wrong turn.