My guild is this way too. I just finished 10th in a tier IV raid despite having 500k+ less GP than ~25-30 people in my guild. The raid is taking twice as long as when we started because it's just not worth the effort and people aren't doing their runs at all, or barely simming a few. The rewards relative to the effort is asinine. 5-7 salvage of three easily farmed pieces plus 1 or 2 purchases worth of currency is ridiculous for something that takes 3-5 days with most of the guild participating. The rewards for posting a zero in the rancor are better and more helpful in actually developing characters to progress in the game.
Please CG, try to make the rewards proportional to the effort. Or at least offer some non-gear rewards that might be useful to people in these tiers like: 4x the credits, purple/omega/zeta mats, good mods (or the currency to buy them), crystals, enough guild event currency to care about (say, at least enough to buy 5 Yoda/wampa shards).
If the raid has to be this unfun it should at least be rewarding enough that the guild doesn't start talking about just not doing it at all as a quality of life improvement.