> That's just how busy people type. You see it a lot if you communicate with upper managers/Csuite regularly. They don't have anyone to impress in private emails, as long as the message is communicated well enough.

There is a time pressure to communicate this way, but I think it's generally a management mistake:

Managment includes leadership (usually). Your messages are most of what most people in the organization see of you. You set the high bar; nobody will prioritize quality and attention to detail more than you. And that standard is global IME - you can't very effectively set the example that messages can be sloppy but nothing else.

For messages to my social inner circle, for example, I am much less careful - misspellings, abbreviations, etc. For messages to people I manage or lead, I make sure it's perfect every time.

Messages from the CEO to the whole company should be carefully checked, and in my experience they seem to be. Spelling/grammar is just a tiny part of check, there is also the whole inclusive language/not offensive to anyone set of checks, and the is this even legal check (perhaps more, that is what I can think of offhand).

Messages to a single vice president get much less care.