Breadth is not the same as capability
A long service list usually reflects what a provider is willing to organise rather than what they perform directly, and that is not dishonest. Subcontracting a specialist task to somebody who does it every day often produces a better result than attempting it in-house. The problem is only that a list gives you no way to tell the two apart, and the difference matters when something goes wrong.
It matters because responsibility and scheduling follow the arrangement. Work performed directly is scheduled by the provider and fixed by the provider. Work arranged through somebody else depends on a third party's availability and their view of your priority. Neither is wrong, but you should know which you are buying before you rely on it for something with a deadline attached and the timeframe you were quietly relying on turns out to belong to somebody else.
