Short answer: Yes.
Long answer: Yes, you are.
I'm generalising hugely here, but as a profession, most IT people (whether it's in software engineering, systems administration or management) can be extremely dismissive of sales and marketing.
This is a huge mistake.
If you're selling a commodity (a commodity is something where the product from one company is much the same as the same product from another company - gold, copper, coal and bananas would be examples of commodity items) - you've got to persuade people that it's somehow worth buying from you rather than any of the other people selling essentially the same damn thing. And commodities tend to have very slim profit margins because as soon as you find a way to knock £0.02 off your costs and pass that saving onto your customers, your competitors do the same thing. There is a damn good reason that every major supermarket has an enormous advertising budget, and it ain't because they like throwing money at newspapers and television stations.
If you're selling something that isn't a commodity and never will be - there's lots of business mentor-type folk who wouldn't get out of bed for less than £1000 per day, even out in the sticks - you need to persuade customers that you really are worth £1000 per day. If your customers get the remotest inkling of an idea that you're not worth that sort of money, you'll be out of a job very quickly indeed.
Then you have things that aren't really a commodity, but your customers think they are. A hell of a lot of technology falls into this category. You're trying to persuade your customer they should be buying software that lets them do X, Y and Z - but they've seen a boxed product in their local branch of PC World that claims to do the exact same thing for a tenth the price. If you can come up with a quick, easy way to resolve this that doesn't involve learning an awful lot of sales theory that doesn't always work - there is an entire industry that will happily write out 6-figure cheques to you.