I feel like you and I must be on different forums. How do you define major modpacks? I look at the Server Promotion forum on the FTB site, and I see seven subforums. One of them for DW20, one for MindCrack, one for Agrarian Skies, one for Horizons, one for Monster, and one for Ultimate. The seventh is for "Other Modpacks." And you know what? That 7th forum has 780 servers listed. That is more than Mindcrack, Ultimate, Agrarian Skies, Monster, and Horizons combined. That is twice as much as DW20, which probably is the most popular single modpack on the FTB launcher. 780 servers decided they did not fit one of the other categories and should advertise elsewhere. I think that your idea of what servers get majority hosted is... flawed.
Speaking of hosting servers, do you know who hosts them? People with the time, energy, and MONEY to do so. It ain't free. To get a server hosted, the modpack has to inspire someone to want to play it. That is why you see packs like Mindcrack and DW20 have the most servers. People want to play the pack their favorite YouTuber is playing. You know what having 10 unique, diverse, interesting modpacks is likely to do? Give 10 unique, diverse, interesting options that might inspire someone to with the time and money to host a server. You know what putting out three modpacks with slightly different mods will do? Take a look at the server promotion area, and look at how many servers are hosting the modpacks that the FTB team controls the content of.
So, by your own metric (number of servers advertised or hosted), the FTB team's attempts to conglomerate huge packs with tons of mods is a failure. Doing more of the same and expecting a different result would speak worse of their judgement than attempting something new.