Marketing involves spending money and it's fraught with the fear of failure (because it often doesn't work).
This mix creates the perfect opportunity to play it safe and to follow the leader.
Jumping on the brandwagon, if you must coin a phrase.
Here's the thing: while the second imitator might make it pay, the third, the fourth, the tenth–not so much. The more you try to fit in, the worse you do. The more you rush to follow the leader, the less likely you will be to catch up.