You ask a great question – Why don’t more vendors create marketing programs that target vertical industries? I think the answer is a bit more complex than you detail in your post. Here’s how I answer it:

1) World-class vertical marketing takes executive level commitment. No commitment, no success. As we mention in “CMOs: Step It Up” (http://www.achievemarketleadership.com/?p=147), this is the responsibility of the CMO.
2) Companies must recognize that this is a significant cultural shift, not a casual “marketing” shift. Products may change. New solutions may be developed. New positioning is required. New alliances are almost certainly required, along with new channel partners. Companies may require a retooling of their sales organization as well. This is a big deal.
3) The vertical “shift” will take time. A long time. Many years will pass before the organization can determine success, and as we know, ROI is hard to measure on this particular topic.

So, what’s a world-class marketer to do?

1) Determine the right verticals. This is based on size (don’t forget telecom!) and your ability to differentiate a solution within a vertical.
2) Identify the hot spots within the vertical. What and where is it that people really want to buy?
3) Determine who the buyers are. You will find they are different from who you sold to via a horizontal approach.
4) Determine what the “whole product” needs to look like. It is different from what you have today.
5) Determine what partners you need to deliver that whole product. You will almost certainly need a new set of alliance and channel partners.
6) Determine your go-to-market strategy (with which partners, with what solutions, into which markets?)
7) Build the teams you need, with the right domain expertise (people who understand that vertical), both internally and externally.
Develop your positioning and messaging around your new solutions. See “Marketing Gets the Message” (http://www.achievemarketleadership.com/?p=26) for more info.
9) Pilot your approach into your highest priority vertical.
10) Rinse and repeat for each vertical.