Also https://twitter.com/Ken1555/status/637902534074437632
This pretty much explains why they didn't preload. If they basically skipped summer vacation to move the steam launch date up they probably did just the bare minimum because that's all they had time for, and now they have no time to spare for Steam because they're gearing up for the post release patch cycle.
Not a question of incompetence, they simply didn't have the time and were in fact burning vacation time.
That's not really an excuse, though. The extent to which doing a pre-load requires effort is thus:
- "Hi, Valve, please change the app state to preloadonly."
In fact, since the app hasn't been modified at all over the past five days, the rationale does nothing more than further the idea that there should have been a pre-load. At least "The data isn't final yet" is a vague excuse that can be supported with "We didn't want people to download a patch on launch day."