It really depends on the situations that happen in your server merge.

When S289 finally got a merge we had 6 groups. We got a merge with a group with a smaller group, and then 2 of the other small groups merged into 1. So there was essentially 4 groups left. My group was the strongest for quite awhile but then other groups started cashing a lot more. They even said that we were p2w people when in reality we only had 4 people who would spend mostly on ninjas. So that changed and then our merged group did a unmerge into one of the other top groups cause they were tired of being in the 2nd strongest group. Which because that happened the group they joined started coming in 2nd all the time quite ironic. Since my group essentially died, I moved to the strongest group, not to win but just to compete against my friends. Then we moved back to my group cause their group was lacking upgrades compared to the 2nd strongest group and My group was only slightly behind the other group their group was level 9, mine was 10 with skills upgraded and the other group was 11. So then there is only 3 groups.

Its never about being a coward, its about being a smart player. Over time after the server merge happens, people will leave and ultimately 2-3 groups will remain.