Verizon anticipated a certain amount of Droid X's to be sold at launch, so they shipped what they thought would be a good number to all of their stores around the country in order to meet demand. They also had to fill their distribution centers to handle all of the online orders coming in on launch day. Well, they underestimated, but so does everyone else, because you'd much rather underestimate than overestimate when it comes to mass quantities of product. Now they are backed up with thousands of orders a day, and still have to ship all of the phones from their warehouses to the distribution centers and their stores.
We can see from people posting that they are receiving emails of shipping confirmation that Verizon is filling orders as fast as they can and in no particular order (at least that's how it seems). The ship by date is exactly that, they are telling us that they will ship it by that date, so chances are you will get the phone before 08/03.
Speculating as to why the orders are not being fulfilled will not get the phone to you any faster. This isn't a manufacturing issue (see: Droid Incredible, white iPhone 4) so I highly doubt Verizon just ordered a small number of phones and then decided to start manufacturing more after launch day.
I also doubt that Verizon anticipated "AntennaGate" over at Apple. That issue grew into a major sh!t storm and has caused many people (including myself) to give second thought to their phone purchase. I think demand for the Droid X went through the roof in the week leading up to the launch and then when Steve Jobs did his little song and dance it pushed many people toward the Droid X as it was the next best option outside of the Jesus Phone.
I was one of those buyers that wanted a phone that would seamlessly integrate with my iMac and MacBook Pro. And that Retina display is simply amazing. There were several big issues that were holding me back, the Antenna issue, Proximity sensor, AT&T coverage, the fact that if I left Verizon I would lose my unlimited data plan, the fragile nature of the iPhone (with the glass back), lack of a 3g Hotspot, less memory and finally the screen size. I have put up with my Storm1 for 20 months and really wanted a larger screen to go with the latest processor speed that is on all these leading phones. High resolution in a small screen ultimately wasn't enough.
I am sure there were others like me that wanted the iPhone4 to be the ultimate phone on the planet, but all the issues above outweighed the Retina Display and Facetime functionality that the iPhone offered. Now...I am waiting like everyone else to get this slick phone. The Droid X offers some key features that most want: 3G hotspot, 4.3" screen, 40gb of memory and unlimited data plan. Finally - I just hated to see Steve Jobs stand up there last week and try to make it out that his problem was no different than the rest of the industry. Total BS...and that was the final issue that pushed me away from the iPhone...despite being a Mac user.
On a nostalgic note - being that Motorolla is one of the pioneers of the wireless industry and Texas Instruments the pioneer of the microchip...it is cool to see them come together on such an incredible phone. Two brands that I would love to see get back in the game as a leader of the mobile communications industry.