So, you didn't solo or duo 90% of the content in XI. You still used pick up groups/alliances or linkshells.
While it's true that you don't need a linkshell to accomplish stuff in XI, it was considerably easier. Yeah, you were badass 75 that all the HNMs were drooling over, but how much time and effort did you have to put into building that pick up alliance for Bahamut V1 alone? 1-2 hours of shouting at least to find enough people on the mission or who were willing to help. Bahamut V2 required weeks of planning, what with needing to farm Ouryu pops from ENMs and then Bahamut pops from Ouryu... A linkshell allows you to plan out events on that scale ahead of time.
As for being the "badass 75 all the linkshells wanted" - don't be a braggart, dude. You just sound like a jerk.