I know what the purpose of a recoil lug is. Up to this point you've been arguing that there should be no movement between metal and bedding material, now you admit there is. I don't need a history lesson on bench rest shooting. The simple answer to the original question is that the floating recoil lug and the rem700 style recoil lug achieve the same results when done properly, regardless of whether one method is cheaper to manufacture or not.
Nobody in this thread claimed that a floating recoil lug performs any better than a rem700 style recoil lug.
First, at no point did I say there should be no movement although I will, here and now, go out on a limb and say this would be the ideal. The truth is, however, that there is bound to be some movement in any assembly given the application of enough force.
Second, in reading at least one post, wherein the clearance in the floating lug was said to be part of an "engineered system" which provided a return-to battery effect, it certainly seemed like the floating lug was being touted as being superior. My point was only that the design was born of a desire to ease manufacturing rather than to improve performance.
That there is bound to be a certain amount of flex as a result of recoil forces is undeniable and there have obviously been numerous opinions over the years on which design would best handle these forces. So it is that we have actions with the recoil lug at the extreme front of the action and the front guard screw located behind it (Remington, Savage, Winchester), actions with the lug at the front and the screw threaded into it (sako), actions with the lug slightly back from the front with the screw threaded into it (Mauser, Enfield, Ruger), and even actions with the recoil surface at the rear (Steyr). While some designs may well deal with flex better than others, any advantages are probably better described as perceived rather than demonstrable. Every design has fostered various theories as to how they should be bedded to best handle the stresses from firing and I think it is safe to say there is still no unanimous agreement in any case.
It has certainly been demonstrated that lugs which are too thin or too small can cause problems due to flex or even distortion of the lug. This is why one sees bent lugs on Remingtons and Savages and this is also one reason for the proliferation of thicker, larger, aftermarket lugs.
When it comes to movement of the action in the bedding, possibly the greatest amount of movement is at the tang. This is especially true in a lightweight hunting rifle. When the rifle is fired the sides of the stock, outside the magazine well, flex outward and the tang will actually slip rearward slightly (this is why it is advisable to provide clearance behind the tang to prevent stock splitting). Once the recoil is over, the sidewalls return to their original state and the tang has to be able to slip forward (well crap! That's kind of a "return-to-battery" scenario, isn't it?). Possibly, managing this movement at the tang may be the most import aspect of bedding, after ensuring recoil lug contact. Again, this may be more a matter of perception than anything else and it has been pretty difficult, if not impossible, to demonstrate what might be the best way to accommodate this movement. Over the years, people have shot with tight rear screws or loose rear screws. Tangs have been floated. The bedding has been lubricated with moly to let the receiver slip or dusted with rosin to try and hold it still. In the end, experimenters can only conclude that their pet method works too because the guy down the line is doing the exact opposite and having the same degree of success.
Savage has no screw in the tang but I'm pretty certain this was not done because of any concerns over tang movement but because there was no room for a screw with the tang safety in the way. That this may have worked out for them to manage tang movement is just a happy co-incidence rather than an engineered outcome.
By the way, solid bottomed actions in stocks with no magazine well are a little different but even though the stock may not flex outward, there is still a certain amount of compression of the recoil lug seat although it is hard to say how much. Still a good idea to clear behind the tang.