XM went essentially from 2007 to 2014... with DreamCabins starting 2014-ish... I found that XM cabins got beat up and tired a lot faster than the DreamCabin cabins... although AC got more new aircraft since 2014 so that may have something to do with it?
But even being on the low 800 FINs (basically the small lot of 788s), they don't seem as beat up/tired after 6/7 years like XM did... IMHO.