The secondary product in a space is more likely to use low context, data driven, us-compared-to-the-leader marketing to try to gain share.
The market leader can talk about the things their product brings (freedom, luxury, attention, healthy lifestyle, etc.) without mentioning the product's features.
Think iPhone vs Android phones, or Honda vs. Hyundai. Both brands are similar (phones and cars), but both have distinctively different marketing approaches.
The market leader also has more leeway in taking the market where it wants to go. A bold sideways move by #1 is viewed differently than the same move made by #2. Its human nature. Which means #2 has to play it safer than #1.
Clearly its more fun the be #1.