Too be fair, zynga is a parasite on facebooks infrastructure. So while syngas direct development costs are low, the real cost of developing what was required to provide zynga the platform is over a billion. (considering Facebook stated their network inf investment has been 1B)

Also, zynga is an idea thieving bandit of a company - so their costs are also far lower due to their hiring people that can copy as opposed to the thought leaders who would have come up with original content.

But if the only metric you choose to measure them on is revenue to expense, then by that myopic unethical lens - sure they look good.