His technical ability hasn't gone anywhere, people are just fickle sheep
Basically,I don't know why rap fans can't just admit they go sick of hearing a nikka for no reason...nikkas just seem less and less remarkable with each album,only ya absolute favorites will survive the cut.
Technically he certainly hasn't fell off but just has become repetetive I guess,he murdered Here Ye and that new single Go Get It "I done mo then you dreamed bout to ya dream bytch in yo dream house on lean passin them beans out"....he can still rap circles around Ross and Jeezy,2chainz or whoever else in his lane.
I do think T.I is finding out what happens when u go for that commercial grab and distance yaself from ya core fans,u gain fans but u losin the core ones the more u make that reach....and the ones you gain being more commercial/pop is usally far more fickle than the core audience who made you in the first place.
If being commercial ain't how you got your fans id say 9 times outta 10 longevity wise and legacy wise its not the best way to go.....off top I can't think of absolutley anybody who its worked out for in the end when u wanna have that long quality 20 yr career and be remembered.