I think the Gate is being used as a heavy means of preventing RMT action. Think about it, for the most part aspects which can be seen as lucrative in 3.0 can only be gained through Ishgard and if the only way to go through Ishgard is via completing up to 2.55 that means RMT would have to complete the whole plot just to progress. That's a lot of work to enter Ishgard and then on top of the risk of being banned for RMT activity. On top of that the fact it's tied to FC in the sense of airships and such which could be the most lucrative means of making gil might also suggest that they can nab RMT whom make a FC for the sheer efforts of making gil to sell.