I know they are a small company and had a lot of shipments to deal with, but they were able to get the books to Alliance early enough that my FLGS had it before any pre-orders. Why couldn't they have started shipping them to customers at the same time?
Sometimes companies have to make deals with distributors that they won't ship product to customers before it arrives at the distributor.
In other cases it is the shear volume of work involved.
Here is an example for you. Let us suppose for a second that the minute the books arrived at the publisher's warehouse they started processing orders. Since distributors often order by the box the easiest orders to process & ship and dealt with first (either whole boxes first or by order size) and those are set out for FED UP* to ship. Then they work on the next and next until as many orders are shipped as possible that day. Odds are there may be either 2+ people dealing with orders (a paperwork processor and 1+ distribution people) or one person is doing the whole show.
So, the first day they unload the truck and them maybe process a few orders. The second day they process all the large orders and start on the smaller orders. Depending on the number of orders they may still be processing orders 3+ days later and by this time the books have likely hit the distributor and in some cases the books are starting to hit the stores. Well, once that happens the orders coming in increase and if it is but one person he may be answering the phone taking orders, processing orders that came in via the web, talking to distributors about books damaged in shipping, and trying to fill tons of oordinary customer orders at the same time. Well, eventually, over the course of a number of days, he has taken case of the distributors, has taken care of the preorders, and is still working on all the new orders off and on fairly regularly for the next month or so.
Now comes the wait for the customer. Books may arrive within 3 days of being shipped or they may not. They may take 6 days or they may take 1-2 weeks to reach destinations within the lower 48 states (and in some cases reach overseas customers sooner). Now then, having shipped 100+ packages (maybe well over 100 ... possibly WAY over 100) it is likely that at least some have "problems". Maybe the name is wrong, maybe the address was incorrect, maybe FED UP mangled the package, maybe it got lost, but for whatever reason a certain percentage will be delayed, destroyed, lost, or rerouted. In my experience it is up to 5% may end up "return to sender", often for a zip code that is one digit off or such.
So, things happen, which is why the old standard of "wait 6-8 weeks for delivery" is still a good adage in my book (and experience) and for anything faster I am grateful!