When you say “a lot of work would look ad-hoc and not well planned,” do you mean it secretly is well planned? Or that it isn’t? I guess the key word is “look”
Sorry.. just saw this comment. It is not secretly as opposed to it might be planned at a director level.. but when it comes to actual engineers, it would not be necessarily efficient use of engineer's time. There is also lot of communication gap and trying to make build everything in 6 months what was scheduled for a year because of various release freezes.