Would depend on the circumstance. If it's due to bad luck on drops then whatever.
If it's due to a loot council style system and they keep giving the same people side grades when it's full upgrades for me then I am all set with sticking around. Unless it's with a group of overall people I really like. Then I speak up about it. It happened to me in WotLK in ICC. Joined a RL friends guild to raid, I wasn't as high ilvl as everyone else so I Was being boosted. We got to sindragosa and kept wiping and some one called me out for such shit dps. I simply replied that I can't keep up with anyone when all pure upgrades for me keep going to other people as side grades. After that I started getting more gear and then started topping the meters. That guild still talks about me being a "legendary" mage in that guild. The only person who beat me on bosses was a really good rogue who still outgeared my by about five ilvls and it would be really close, then we'd have a drop-off for third and beyond. Needless to say that person apologized for calling me out after he saw what I could do with good gear.
So yea, the whole thing would be situational based on the raid group I'm with. My issue is I always tend to end up getting sick of the people I end up raiding with except that one guild I gave an example of in this post. I keep trying to find a long term guild to raid with but nobody sticks long term.
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