Using the example from the article: "K let circle back nxt week bout it . thnks"
I'm not buying your argument. The amount of additional time that it would have taken to write that same message with proper grammar and spelling is minuscule.
typed on a phone, so unlikely to have been at the office.
The boss was following Strunk & White's advice to omit needless letters.
That depends on your typing ability. My mother only looks up at the end of the sentence to see if she hit all the right keys.