Part of the problem Alex is seeing (and I've seen) is that the startup/small business segment just isn't that big, and vendors are usually fine with ignoring it and losing out on revenue. I do a lot of stuff on the side and have tried to buy licenses for some enterprise products, and even mid-sized vendors aren't really interested in talking to me. Large vendors like Oracle and IBM are heavily optimized toward selling to big businesses who need a purchasing process to take months and aren't as sensitive to price. The App Store model is 99%+ consumer-oriented.
Unfortunately, a lot of startups and small Enterprise vendors end up recruiting sales and marketing people who have been successful at larger vendors, so the same practices get implemented.
I blame this mostly on purchasing practices that are largely centered around managers mitigating risk. The risk they are most interested in mitigating is the risk that they'll get fired for making (or approving) a bad purchasing decision. Vendors are happy to play along, since it usually means they can make more money out of the deal.