A mechanic that tells you to play a lot of monochrome permanents, while intrinsically interesting, is not extrinsically compelling in a format as high-powered as Legacy
Or, possibly, Charizard has reached its hottest possible level
So what tends to happen is that eager beavers will trade for a couple of pieces from some exciting new deck (generally right after they see it perform well on stream and the prices are at their highest) only to give up once they realize, holy mackerel, Vengevine is itself a $50 card and Leyline of the Void is up to $60 and you need a playset of Arid Mesa and wait, how much is Blackcleave Cliffs these days
Jund Sacrifice is one of those combo-style decks that demand high levels of familiarity from the pilot
As the name suggests, Meek Attack is kind of like Sneak Attack, in that you can use it to cheat a creature into play
The best card in Foundations Jumpstart has to go to Dionus, Elvish Archdruid (though Rev, Tithe Extractor and Scythecat Cub are strong contenders)