I view it as sort of a gregtech mod you know. People wouldn't play it with other tech mods installed because it would be kind of hard IMO
Therefore they wouldn't waste time to make a pack for a handful of REALLY hardcore players
Just my opinion
TFC has been increasing in popularity lately. Especially after the introduction of its launcher. The hardest part about playing TFC was always the installation process, which was easy to get wrong. Nowadays that is no longer the case, and so many people who never bothered before are now giving it a try.
Also, you could use some precision of language. If you want to state that "TFC will probably never be added to FTB, the challenge map", then you would be correct. If you want to state that "TFC will probably never be added to the FTB launcher", then that's pure speculation on your part unless you can produce a quote from a person on the FTB team to back up your claim.
In general, it is bad form to include speculative statements in your posts. If you must, tag them as such, but better still is to avoid them entirely. People WILL call you out on them, and that gets awkward quickly. And it gets even more awkward if other people lap up your speculation as fact, get called out on it themselves elsewhere and then point the blame at you.