there is plenty of that, Total chaos was a seriously reworked version of the tracks campaign from the Jihad books, but a consolidated product was needed to bring those together (and get the tracks from Dawn, 3072 and the Blakist documents in line with Chaos Campaign).
Likewise the Year of the Star league would naturally have a lot of materiel recycling since we are beating the drum of the same force over and over. at one point you do not want to hammer certain facts home, but you do need to, when appropriate, repeat information, such as how the SLDF organizes itself rather then rely on players to refer to books they may not wish to purchase.
History will show that the Year of the Star League was a success, but only just, and the Battletech Line Developers (Herb Randall and Ben) have already learned that player buzz on does NOT translate into sales.