Why cabinets go in before the countertops are measured

The template does one job: it records where the finished cabinet tops actually sit, not where the drawing said they would. Work booked through riverside kitchen remodeling milestones calendar puts the template visit after the last cabinet is set and fastened for that reason. Measuring a Riverside kitchen before the boxes are in means measuring walls that have not yet been fitted around them.
What happens when the cabinets are set?

The installer finds the high point of the floor, shims every box to level, and screws the run together through the face frames. Then the run is fastened to studs, which in older plaster houses near the Mission Inn can sit further apart than the drawing assumes. Any box that was a quarter inch off at the start is a quarter inch off all the way down the line, so the leveling comes before anything else.
Why does scribing matter to the counter?

A wall that bows is closed against with a scribed strip cut to follow its curve. The cabinet position moves slightly while that happens. A counter measured before the scribe is a counter measured against a position that no longer exists, and stone does not forgive a gap that was supposed to be closed.
What does the template visit record?
The fabricator lays thin strips or a digital scan along the cabinet tops and marks the sink and cooktop positions, the overhang, and where each seam falls. In Riverside, CA the visit also catches things a drawing misses, like a window sill that sits proud of the wall or a corner that closes at eighty nine degrees.
Why does the sink hole wait?
The cutout depends on the faucet, the sink bowl and the base cabinet behind it. A drop-in sink and an undermount need different edges, and the bowl has to clear the cabinet front. The sink model is therefore chosen and on site before the template, since changing it afterward means a new cut or a new slab.
What does measuring early do in practice?
Usually a remake. A counter cut to a pre-install measurement is the one that arrives and does not fit, and a rejected slab takes the whole fabrication wait again. The few days between the last cabinet and the template are the cheapest days in the job, whether the kitchen is near Fairmount Park or out in Riverside County. Give the fabricator a clear date for the last cabinet and a clear date for the plumber, and the template can be booked back to back with the fastening instead of drifting a week.