Did you really take a marketing class?
First of all of the phone makers have had proprietary OS at one point or another. It is a very good thing that most of the phone vendors deciding not to "roll their own" operating systems anymore. The Iphone's success vividly illustrates how users were desperate for a smart phone with well designed user interfaces and a functioning third party software developer market.
Secondly did you ever take a marketing class? It's called market segmentation. The Droid and IPhone are both well designed phones, but the feature mixes appeal to different market segments. Apple had first mover advantage and chose to replicate their desktop strategy that relies on creating the impression of extreme ease of use. Google has crafted a reactive strategy that is analogous to Microsoft Windows (the HW vendors battle it out and we control the SW) and attempts to grab the market share that Apple left on the table.
The tech savvy individuals who consider themselves power users and are not put off by complexity and see technical difficulties as technical challenges to be overcome. This population resents being kept in a "walled garden" and will serve as the pioneers who blaze the trail. In broad terms this Ubergeek population skews male and the ease of use population skews female. Clearly there will be individuals in both groups who do not fit this model, but successful marketing is about understanding the large scale market dynamics.
In short the droid is positioned to cleave off a hunk of the Iphone's male demographic. The Iphone will continue to be more attractive to people who put a premium on ease of use. Once the droid is established as a successful smart phone there is no reason that Motorola can not put out a new ad campaign that stresses ease of use, or reduced cost, or more carrier choices.
This is just a short term strategy that accomplishes a short term goal. They need to unseat Apple's Iphone's hegemony so that average smart phone customers will consider a droid.
The one valid point you touched on was that Mot is one of a pack producing Android phones. Under the Android banner strategy there are two winning strategies. Either be the lowest cost lowest common denominator android (Nokia or Samsung if they go droid) or be the technological leader. If you notice Mot's Droid in Android 2.0 whereas the others are at Android 1.5 or 1.6. This signals that Mot is following the second strategy which is better for Mot since they cannot do the economies of scale thing as well as others.
Given the options that were available to Mot this strategy is better than most. I hope they stick with it and be the preferred Android manufacturer.