The loss of the social effect is going to be big in companies I think when it comes to hiring, the best technical person is not always the best choice. Work from home narrows a persons ability to stay in touch with the other departments they do not directly work for.
The opportunity to lend a hand to another department gets removed. When in a work environment there is the coffee breaks and the meet-ups not just with your department people but others as well.
No more casual compliments to your bosses boss on the help you gave them or on a suggestion you offered up in over hearing a conversation. I imagine word of mouth from outside the department people work in is going to slowly go away.
I think the same. In the short-term, companies will be happy due to the cost savings, but as time progresses, if they aren't able to introduce the randomness of personal communication and interaction, the costs are going to mount up fast. I reckon that for many companies, they are going to see a reduction in some types of innovation.
Word of mouth plays a lot in promotion in any company. If a person is well known in their department only, and another is well know in theirs and in a couple others, the second stands a better chance of being promoted. In an on-line work environment I would imagine it is difficult to get that word of mouth contact.
It is difficult and it is easy to be caught in the bubbles - thinking one is more spread than reality.