You're absolutely right that conventional chicken is the hardest nut to crack when it comes to achieving price parity (beef and pork are easier), but I'm much more optimistic than you.

In 2013, the first cultured burger cost $330,000 to make. Just under a year ago, Memphis Meats was at $18,000/lb of clean beef produced. Now they're at $9,000/lb. This is before any sort of efficiencies from scale, and before many steps of the process have been anywhere near fully optimized. They expect their costs to reach 2 cents/g by 2021, which would be cost competitive.

And while chickens are somewhat efficient, they're not as efficient as culturing techniques ought to be at scale. Memphis Meats' process will require 3 calories of input to produce 1 calorie of beef. That's just better than chicken, and massively better than beef or pork.