I think the hard facts support the assertion that there are currently 2 grades in F1,
Manufacturers or exclusive works teams = A
Customers = B
Unless there is an alternative argument that says otherwise
I think saying there's an A and B grade is suggesting there is two categories in F1 or it's like a premier league team to 1st division.
Being a works team isn't the be all and end all in F1, Redbull have proven that.
This is exactly what I meant by B grade. Mercedes will not be expecting their clients to outperform/outdevelop them, that would be a major embarrassment for both Mercedes and Ferrari if it were to happen.
Didn't mean to insult McLaren whatsoever (I finally have newfound respect since they the coup happened) but they are essentially a B grade team heading into 2014. From 2015 though they have a better deal since it's an exclusive one with Honda. But still not a purebred engine/chassis deal under 1 roof.
EDIT I misunderstood you. What you say about RB is true, they proved being a works team you can still be beaten but as repeated
time and time again, we are now in the engine era more than the aero. The balance of power has shifted massively, and from now onward being the works team WILL BE a major advantage.