Because the Noctua has a lower sound rating?
Cause its Noctua (and if there is an NF-F12 fan on the heatsink, that would be worth $20+ of the heatsink's total cost)
A quirk of Supply and Demand, for instance a H100 is selling for $30 more than a H100i on Newegg, simply because the H100 is out of production and becoming rarer.
Some products are just better than others, and the 212 EVO is a very respectable heatsink that is known for being great value. There's a reason why its so popular.
IMO, no point in buying mid-range cooling. Just go with the 212 EVO, and if you want more cooling, jump straight to something like an NH-D14.