[I mean: when both the main road and the secondary road that has to yield are clogged, everyone on the main road lets one car from the secondary pass.]
I've certainly applied it and benefited from it countless times.
We have a slightly different problem: people don't understand that the full capacity of the road should be used, zipping only shortly before the constriction. People switch lanes far too early, other people pass them (because the lane is free until the constriction), people who switched early feel cheated, everybody gets aggressive.
And any attempts to use the free lane will result in cars dangerously cutting you off.
In very low density traffic on high speed roads, waiting until the lane is actually closed to move over can create slow downs, but moving left earlier doesn't. The point where the optimum behaviour changes isn't always clear and can change rapidly.
In the UK, the rule is that in slow moving congestion you should late merge but in other cases you should stick in the left lane unless overtaking. There isn't a specifically defined point where one behaviour should take precedence over the other.