I can see his point if you have 90% of the workforce in the office and 10% away who might be missing out in inane banter but also the spontaneity of collaberation.

However a workforce becomes designed around WFH it can become beneficial as employees might have a meeting whilst walking their dogs at the park or go to the local pub for lunch and a brainstorm. Its not so much working from home as it is moving the office outside.