I like Gemma, but I get the feeling that she is either tired of modeling (and just shows up every now and then so people won't forget her just in case her other career does not take off...). Looking at this from the business side of things, it does sound like a business decision: she may just want to position herself as something like Natalia/Gisele/Daria/Hilary/Liya/VS models who just show up whenever they feel like it (they do have $$$ long-term contracts though, I suppose, so they can afford to do this? But who knows, Gemma might have been an investment wizard or simply accumulated enough already so why bother competing with younger/hungrier models when you are at a certain stature already? It's inevitable, there's always gonna be somebody who's younger and new, so why not quit while you're ahead? In that way, you are taking care of your own brand)...
I do not get why people pitt Gemma and Sasha against each other. I think their features are very similar. I do admire Sasha, it really seems like her work ethic is very good, and she always delivers. Even if they look eerily similar at times, they have a different feel, give out different vibes. I don't think Sasha would've been able to create the same dreamy/romantic feel that Gemma had when she did those Roversi/Meisel edits early in her career and I don't think Gemma can look like she can cut a b.itch in those Vogue Paris edits like Sasha has done. They have very different brands and they can't be marketed the same way. They may look alike but they are not interchangeable. (And if you look at career arcs, isn't Gemma more like Stam's, Lily Cole, Daria's generation? These people seem to have opted not to be that visible too, right?)
There. Just had to say it.