Such a great description. It's every reason that I hate MMOGs.
That said, I think their "the game starts at 80 model" does work for them, because it forces everybody to play through all of the content. You might think, "Why would people play a game that isn't fun just so they could get to the good stuff?" If people were rational, that would make sense, but we aren't always rational. Many of us will think, "The end game must be really good if all of these people played for weeks to get there and still play it," so they force themselves through it. They may hit the end and decide it wasn't worth it, or they may actually like it and stick with it, but either way they have played for a long time and spent a decent amount of cash.
Now, what if it really was a sandbox and everybody could play what they wanted? Assuming each group likes a small subset of the game, they would go off and play that subset, experiencing only the content they liked. It would take them a fraction of the time to do this, at which point (like everybody else who gets to the end), they would eventually get bored and demand more content. Now Blizzard has to make x-times as much content in order to keep each group busy.
It's the difference between Ikea and Walmart. In Walmart, you can walk it, get what you like, and walk out within minutes (if you know what you want). In Ikea, you have to walk through a serpentine maze for 30 minutes or more, forcing you to experience everything. We still do it, because there's a pot of gold at the end of the rainbow, but we still wish we could just get what we want. But Ikea does this because it forces us to see everything, rave about the selection, and possibly pick up something on an impulse. It's all about extending the shopping opportunity. For Blizzard, it's just a matter of extending the subscription period -- hopefully until the next expansion is ready.
All that said, I would give MMOGs another shot if they gave me a chance to do the fun things without grinding for weeks.