I agree. No, actually,
I don't disagree ... which is not the same, and here's my thinking.
Early doors, when I first came to traditional shaving, shimming was in vogue. I recall doing it ... and yes, it made a difference. Yes, the blade gap can make a difference. I say "can" and not necessarily "does". You're right
@Greybeard it is about the angle.
Once I had shaved a while longer with traditional razors I gained a sort of sixth sense about how to pick up pretty much any razor and get the angle. I think what I'm doing is connecting with an angle in relation to the top cap where the blade edge is more an extension of the blade cap and takes its relationship from that, rather than taking its relationship from the guard ... where blade gap might make a difference.
I think I can say this with some confidence as there was also a trend towards what we called SEvette and DEvette razors for a short while. What are these, then? Well, you take a safety razor (any safety razor) and you snap off the guard. Gone. Now you have, quite literally, an infinite blade gap! When I shaved with a DEvette (I think it was a GIllette Tech with no guard bar), I got the self-same shave I always got.
^ Look these up. It's worth a giggle. Stunt shaving at it's best!
One of the earliest pieces of advice I got about shaving with a DE was to place it flat on your face with the handle sticking straight out perpendicular to your face. Now, lower the handle until the blade just catches. Lower a tad more and you're there - that's the angle, and that's how I approach shaving, albeit getting to that point more quickly and more naturally nowadays.
So, I rather wager that I could get the same shave from a 1 plate or a 6 plate ... but I've never tried a Rockwell 6S, so I don't actually know. And, I bet if I did own one, I'd settle on the 3 or 4 plate, because that's what folks do. What is probably for certain is that the 3-4 plate gets the shave that folks want more readily/easily than a finding that fine angle on the 1-2 plate across all contours of the face.
Put another way, where the optimal angle is not kept absolutely bob-on for the whole face and whole shave, a blade gap will fill in for technique. I guess we call this "efficiency" because we require less precision to get the same end result. Get to know a razor very well and you'll find it hard not to use that optimal angle. We gain that sense memory from repetition and something like dragging a sharp blade over your skin is a sense memory that gets learned fast!
Let none of this dissuade you from making a purchase that you want to - this is all about having fun, enjoying the gear we buy and getting a shave out it! Probably in that order, or we'd just use a Gillette Dyson Flexbomb.