This tirade against Scott McCloud could probably be summed up in a few sentences: "Scott McCloud's optimistic view of the future 'level playing field' of digital content distribution should be framed in a larger context of corporate power and influence over the internet and information distribution in general." There is, however, little need to attack McCloud's rhetorical, even hyperbolic style, unless you're trying to attract attention to yourself.
I would add that there are still reasons to get excited about the possibilities of digital distribution. When distribution is diminished as point of control and extortion, then more attention can be focussed on the artist and the work itself. However, with fewer limits to distribution comes a greater emphasis on promotion. This is why in the long run, it's crucial to not let Microsoft (or whoever) to control the way we look for information on the net, just as it is crucial not to let commercial radio stations have monopolies on what is broadcast over the air.
Both Microsoft (and Yahoo, Excite, etc.) and commercial radio stations are focussed on one thing: profit. This means that, for example, the record industy's chokehold on distribution can be transferred to a chokehold on the ways people find out about tunes, by dictating what is played on the radio (which they do now), by dictating what options show up when you use the RealAudio or Quicktime player (which they also do now), or by gaining greater influence over what content is featured prominently on popular web sites like Yahoo, MSN, AOL, and Excite (which happens to a large extent on MSN and more on AOL, and slightly less on the likes of Yahoo and Excite). There's always the Open Directory and Google, which are in many ways vastly superior to their more commercialized counterparts.
In this sense, the "revolution" of online distribution isn't likely to be as clear cut as we might like, since powerful (read: moneyed) interests aren't interested in losing control. If they have money, and AOL and Microsoft want money, then it's only a matter of degree to which the "revolution" is marginalized by selling control of "eyeballs" to the highest bidder.
This is not to say that things won't change for the better with online distribution. To what degree they change, or are revolutionized, is dependent on the alternatives that are built. And that's up to me, and you.