If you are looking for a number 1 receiver then you need to draft a guy who projects to be that. Otherwise you go a different direction. Sure you might get lucky and draft a guy who surprises like Smitty himself but we all recognize that he is one of a kind. If we had 12 picks then you can waste one on a receiver and take a flyer. When you have 5 picks you have to make everyone count.
you can say that about any position except maybe guard.
sure things don't get out of the top 10 unless you are really lucky.
you say "project to be a number 1" but the standard that people arguing against drafting one have been using is the incredibly rare types like megatron and aj green. they don't have to be that caliber to be a number one. you should get the best player possible, but you should also be realistic out the expectations for the guy you draft mid to late first round. you may want elite talent. they may wind up being elite talent. but you don't not draft someone because they aren't assured of being elite talent. you want the best players you can get, but the later you pick in the draft, the less of a sure thing they are and the lower the ceiling might be. if you need someone to come in and take over that top spot, you don't sit around and wait for that sure thing and if you want to try and answer that need you don't take a timid approach and take low risk high reward guys hoping that you'll luck out with one. if it's important to find that guy you understand that you might have to take a risk...esp. if you don't have a very early pick.