Maybe “necessary” is too strong, but “likely pivotal” is better.

If VR becomes widespread, and amazingly high quality, then almost everything we do will migrate to VR.

Once that is the case, we will have an unprecedented amount of data about human behaviour, and near endless data for training, experimenting, and testing AIs.

The problems of AI will become much easier to formulate: “replace this person in this VR scenario, interaction” etc. This will help drive research by giving clear goals.

More pragmatically, it just removes a lot of barriers to research and accidental difficulties ie you’ll just be able to fire up a VR rather than worrying about how your robot is going to pick things up or access real world data etc