In some modern aircraft such as the Airbus A380 or Boeing B787, the callout of the V1 speed is automated through a synthetic voice, based on the V-speeds entered into the flight management system. However, the rotate speed VR is still announced by the Pilot Monitoring. Why is the VR callout not automated?
from my experience (A310, A320 family, A340), V1 and VR speeds are often very close together, sometimes they even are the same.
The automatic callout system can only output one signal at a time; during landings, one can often hear the decreasing radar altitude callouts being overlapped. Therefore, the VR callout would often supersede the - more safety relevant - V1 callout.