I originally wanted to write a long post explaining why I, an opensource software developer, think bitching about modpacks is rather stupid thing to do but I'll just leave this little bit of information:
Technicpack serves around 1TB (~1000 GB or 1,000,000MB) of data per day to it's users.
How many mod authors have the resources to offer similar service?
How many of the individual mods get anywhere near the exposure as they do inside technicpack?
Also without the pack I'd still be playing vanilla. Some mods are pretty nice but I simply don't have the time to combine the stuff I like myself and I'd simply wouldn't do it at all if I was forced to.