If they had a line that was for the RPG and not TT legal then they could. I will never EVER pay $40 for squad of GW IG. But if they offered a cheap alternative like DnD/Pathfinder where you can buy individual mini's for $5-6 then I'd gladly get behind that.
You need not shoulder that burden individually! If you have a group of 5 players (Fairly standard) you could each chip in to buy said squad. It would cost you $29.00 through the GW website (NOT $40). That gives each of you a character and their comrade for approx. $6.00 apiece. You could also check out Ebay as their are often whole IG armies going for quite a bit less than their new price. Some are even VERY well painted!
The Emperor protects! (The GM does not!)
Of course, that'd likely be just a couple Cadians … unless you get lucky and find an offer for one of the metal regiments on ebay!
My group/s only ever used maps, marking people's positions with pencils, or using some sort of token. This is what I would recommend, as it seems like a good compromise between people not knowing what's going on and meticulously marking every single step of a character. With maps, you can make sure that everyone has an understanding of the rough appearance of the battlefield and where their allies and enemies are located, leaving the details up to their imagination. :)
The only time I ever used actual minis was in a short campaign of Saga Edition Star Wars, and though that was pretty fun I still would have never considered it a true necessity.
current 40k RPG character: Captain Elias, Celestial Lions Tactical Marine