Both Boeing and Airbus make good airplanes. Nevertheless, they hire expensive salespeople and pay them massive commissions. They don't just tell the airlines to download a pdf brochure of the planes' specifications and call them when they're ready to place an order.

People making statements such as "good products sell themselves" are probably thinking about gadgets like iPhones that don't require "greasy used car salesmen" with high-pressure tactics to close a sale. Yes, the Apple employees at stores are more like order takers than salespeople.

However, many well-engineered products absolutely require salespeople to close the deal. I was recently researching $100k CNC milling machines -- there are several brands with quality engineering and yet they all have salespeople to guide prospective customers about configurations and persuade me to buy. Trying to decide purely based on information posted at the manufacturers website and printed brochures would be unwise. Yes, the general "concept of a CNC machine" sells itself but a particular brand & particular model of CNC does not.

As an Account Manager, I research about my customer and reach out to them once I am convinced we can add value. Not just sell them stuff.

But you can't trust what the company says about its own product, so you really you're talking to someone who can negotiate a contract where you get your money back if it sucks.

If they get their money back, does the contract negotiator lose their commission again?

That's very true if you're selling something with a low value (most things consumers buy really), but you're dreaming if you think you can sell a technical product to a business for $10k + without salespeople. Enterprise sales is more like project management than what you probably think of when you hear "sales." Especially when you've got to pass through engineering, finance, procurement and legal to get a deal across the line.

That's not necessarily true. There are thousands of examples of good products that failed due to lack of marketing.