I once worked for a company that had an average sale well under than $100,000 but that sale typically included several licenses for at least two different products -- one a desktop app and the other a SaaS offering. There would always be at least a day of training, and possibly some consulting services and the possibility we'd bundle in something from a vendor we work with.
If customers tried to set that up with a web form they'd screw it up and hate our product.
Similarly, something like an ERP or Library Management System is going to take a considerable amount of attention from the vendor to fit it to your needs, so the salesperson isn't just there to harass you, he's there to make sure you get what you need to succeed.
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I'm working on a product now that I could have sold through an impersonal automated process for $50 a month... If I could get enough subscriptions.
I didn't believe that I could, and decided to price the product much higher and sell it through a "high touch" process so I could make a living selling it to a handful of customers.
One issue is that anyone who sees the price would get sticker shock. However, the price per year will be between 1/3 and 1/4 of what it would cost to develop in house, and it would be charitable to estimate that most organizations would have 50% chance to produce a product that works (almost) correctly... After losing a few months on the schedule! Plus my product is documented, supported and comes with a pretty bow on top.
My guess is that for the value this delivers to customers it's worth my time to explain to them the value they're getting.