It's been a long time since folks relied on salespeople for information. Some say that died with the internet but I believe it's been longer than that. The so-called Information Age didn't begin with the internet..though it got a helluva boost.
It's true, for decades, businesses and people relied to a degree on salespeople to learn about what's out there. The overwhelming majority of salespeople would tell them "what's out there" all right. What's "out there" is actually in the bag I'm toting around! In fairness, that was their job. This practice still goes on today in certain industries(e.g. pharmaceuticals).
It wasn't long before U.S. corporations decided they liked the moniker "Sales Consultant" more than the many variations of Sales Rep. I always found the title Sales Consultant hilarious. Ask your Acme Widget Sales Consultant which other widgets- aside from Acme's- they recommend. A professional consultant is an expert who gets paid for their non-compromised advice. To earn a decent living as a consultant, you need to really know your stuff. And when it comes time to advise your client on what products or services to buy, a commission is a kickback. Fine, I guess, as long as you reveal it to your client. It's actually a common practice in professional consulting but I'm not so sure how often the customer knows the consultant is getting a spiff. If the consultant recommends something they don't believe in or are entirely ignorant on, they best keep their eyes peeled for the Karmic Train heading their way.
Today's salespeople whose sole responsibility is to manage existing accounts are required to promote upsells. That's really the only thing they're measured on. If sales are flat (or worse) with an account, Hell is on the way and hell is bringing their manager with them. What's called a "sense of urgency" internally with the vendor is really the panic button being pushed repeatedley. Instead of getting creative companies get aggressive first followed by desperate.
As an Account Manager, your job really involves just two things. You need to be an EXPERT on your customer's business, especially in relation to how your offerings facilitates their business needs. Secondly, in the age of insanely piss-poor customer service, you need to offer world-class customer service. That's a HUGE value to your customer. Constantly trying to upsell them is not. Lastly, you need to be an expert on any product/service your company offers that your customer may be interested in. Just having information about your products is useless, it's a mouse-click away. If you represent technical wares, "let me reach out to my engineer" can NOT be your default response to every question. You will be eminently expendible to both your customer and your company if you can't solve basic technical customer problems. Some products/services are EXTREMELY technical and the sales engineers are constantly being trained so common sense prevails here but the account manager, at minimum, should be able to handle technical questions that are frequently asked.