I can agree with you that Cavani's numbers are as bad as Higuain's, but you gotta look at more than just numbers.
Look at their respective teams, Cavani played most of his CL with Napoli and PSG, with Napoli he'd rarely get passed group stage and with PSG they would consistently get knocked out in Ro16. On top of that he was slapped on the wing and had to service an even bigger choker of CL then Higuain in Ibra.
Where as Higuain at Madrid had absolutely 0 reason to fuck shit up, he had some of the BEST supporting cast out there, and he was choking vs Lyon, like 3 seasons in a row....

same thing in the national team, he plays in THE most offfensively blessed team out there, where as Cavani plays in 2nd rate team (i still love uruguay, im a fan) with very little support. The Uruguyan strikers hardly get a third of the goal opportunities that the Argies get.