Not to say we're free of challenges... but hey. We can make this happen. I have a couple racks in the space where car doors are expected, yet can still park.
Think of the business continuity wins! Each employee has a Starting Google!
Then there is latency. Most apps talk to a data store, which is now separated from clients. The load balancers are going to be separated from the backend. Also, database servers tend to be beefy servers so either need to shared it or someone hosts a rack.
Another is that need write software to really be distributed. There is difference between distributed when things break and distributed all the time over the internet.
With 1Gb+ residential internet speeds, you could probably build a fairly robust and scalable platform like this.
How many people do you think have symmetric gigabit? The company is going to have to pay for employees to upgrade. And do some separation to keep from saturating link from either work or home.