Because the exchanges are shady as shit, and it's hard as fuck to into bitcoin. This is just another nail in the coffin for bitcoin adoption(NEW PARADIGM!!!1one).
Bitcoinfags think that bitcoin will just constantly rise in value, not thinking on what it means for bitcoin to be a currency(used as an exchange between two parties) vs a speculative instrument. Further, it's NOT untraceable(coin tumblers help, but they're not the default, and possibly not foolproof), so it fails that libertarian ideal. Combine that with the high barriers to entry(ASIC mining, electricity cost), the ponzi scheme nature(first in, $$$$$$, last in? $), the ever widening wallet size(6GB and counting), the 51% mining attack, the sketchiness of these exchanges, some of which have been shut down for money laundering(even if Bitcoin is free'd by the FCC, that doesn't free up the institution's responsibilities), the slow speed of transactions(I think the network can handle 7 transactions a second max, some transactions supposedly are REALLY slow)and, well, it's a recipe for disaster.
Normalfags will never embrace it.
Silk Road is dead.
And keep in mind, Bitcoin is the first and most prevalent bitcoin. Altcoins almost all have NOTHING going for them. Most of them are just pump and dumps, very few bring any ACTUAL features to the table.