Not necessary IMO. In December 2018 they introduced red and silver beads, and before that, in August 2015, they went all-out with their HD launch graphics. Those were more than enough and multiple changes every couple of years are unnecessary, unless you are Colors Kannada or Sony Sab, which keep modifying their graphics every now and then.
Channels that don't need to rebrand are rebranding, while channels that need to rebrand (Jalsha Movies, Asianet Movies, Star Movies to name a few) are not bothered to rebrand.