No, things measured in different units are not comparable in size. The “comparison” is like marveling that the distance between two cities (in miles) has approximately 2/3 the value of the speed-limit on some road in miles per hour. If the road connected the cities it would tell you that it would take about 40 min to get from one to the other, but otherwise it’s silly.
(2/3)*(NZ GDP in US$/year)having approximately the same numerical value as Facebook’s market capitalization in US$ is a pointless “comparison”.
You’re being small-minded.
He’s making the comparison in the sense that you might say you could have listened to Wagner’s ring cycle in the time it took you to see a doctor in the emergency room.
No need for equations trying to compare music and medicine, the key point is made simply.