If the target customer group needs sales staff (such as B2B solutions for decent size companies), then you will need direct boots-on-ground sales staff anyway - it's not even a matter of competition, it's table stakes to be able to participate.

If it's B2C / mass market B2B then sure, a website can do half of the job; but there are huge markets where even they really like your product and they call you, then 0 sales will be made unless you get a sales rep in their office.