Being a Ralph Lauren contract model is one of the biggie contracts a la Victoria's Secret, Estee Lauder, Lancome and Calvin Klein, they just don't seem to promote it as much as the other brands mentioned. Not to sound snarky or anything, but referring to her as irrelevant is like referring to Hilary Rhoda or Doutzen Kroes as irrelevant models because of their decreased presence after they signed their contracts. She still does a little bit of runway (I think) and editorial work, I may be wrong about this but when she crops up in a non-Ralph Lauren situation, it tends to be Russian / Eastern European publications.
Having said all that, I do think that it is not wise for models to curtail their activities when they sign a big contract and should be somewhat visible in print and on the runways, provided that they are not violating the terms of their contract.
ETA:
Although I have wondered if in Ralph Lauren's case, with their main face if they don't want her to be known as anything other than the Ralph Lauren model and as such pays her well enough to not pursue other stuff, but I do think that they can still do some editorials and runway. My thing is that it is a Catch 22 for a model, because it is a big bucks contract but when the contract ends, and if she wants to continue modeling, she has to, perhaps not start at square one, but start at square three or four with her modeling career. Hopefully they is a good financial planners.