If the Talk Back section is a good guage of retailer sentiment, I'm obviously in the minority when I say I'm in favor of Marvel's policies.  I'd like to add a few more thoughts:

Marvel's policy of not making material available in overprinting/second printing definitely hurts future sales, since my customers are reluctant to buy a #2 without reading #1.  That's why it's important that Marvel provide the Must Haves expeditiously.  I agree that the readers are usually the most consistent and loyal group of customers.  However, it's impossible to predict how many copies you could have sold to these readers'if only they were available'.  If every retailer were easily able to reorder and receive every 'hot' Marvel book, I bet there would be gobs of unsold books in our backrooms (Dark Knight Strikes Again, anyone?).

I don't look at selling back issues as 'gouging' my customers.  Once I've succeeded in fulfilling all of my steady customers' needs at cover price, it's a business decision to stock back issues.  This isn't holding back, it's determing your inventory needs.  Currently, my inventory needs involve selling x number of issues of a hot book for 4 weeks at cover price to all who want them and also x number of copies for back issue sales.  The only way to do this profitably is to charge a fair market price, with higher margins(60-90%) than new product(30-50%).  There's simply no way to pay for the labor, space, cost of goods etc. to provide these back issues that my customers want, and still offer them at cover price.  Doing back issues is tedious, labor-intenstive endeavour; I don't blame most retailers for ignoring that market.  If you are a store that wants to offer them, Marvel's policies are the most rewarding.

Another reason back issues are important:

I simply don't see how I can make a decent living selling only new product in my stores.  Whether it's back issues, single cards, vintage toys, or whatever.  You need those higher margins (60-90%) to offset all the low margin stuff that either doesn't sell through or that turns over very slowly.  This is why the new action figure and new statue business is so harmful to comic retailers.  Bad margins, low turnover, space-intensive.  I seriously doubt there's any comic shops out there, besides those in very high-traffic locations, like a major mall or major downtown city, that can really make a decent living selling exclusively new product.

Yet another reason:

If I'm to compete with national chains, I have to carry stuff that they refuse to or cannot logistically sell, like back issues and single cards.  Otherwise, why would someone need us, besides the fact that we're all really god guys?