First, you did nothing wrong. You can very easily, very obviously, compare Apple's market cap to the total annual economic output of a nation, or the economic output of any thing over a given amount of time.
Apple's market cap of $2 trillion, is greater than the annual economic output of the nation of Italy's 60.3 million people ($1.98t 2019). You just got told that is impossible to do. I just did the impossible. Which do you think is more likely true? It's obvious.
It takes the 60.3 million people of Italy a year to produce enough total economic output to almost match the total value of all outstanding Apple shares. Oh shit, I did it again. A spontaneous blackhole may appear and we may all die. I just successfully compared two things everyone repeatedly says is impossible to compare.
You can obviously compare the two, and do so quite cleanly, have no fear.
I've been watching this herd action for a long time here. People don't seem able to stop and think about the context beyond a primitive twitch action, they just reflexively downvote, and parrot the same responses ad nauseam (it's always the same responses without exception).
Second, you have to understand, you're facing off against many people's favorite "gotcha" Smart Person(TM) response. It's an arrow they hold in their bag, for times like this, that helps them feel smarter than you (that's why you'll see so many of the same response, unnecessarily; if they were right, one would be enough). They may not know much about economics or the stock market, however they know this thing, they saw it somewhere else, it sounded true, and they can feel good by downvoting you and by drowning you in one line responses. You deserve better dear user5994461, for your four years of HN dedication and contribution. I want you to know that what you did is perfectly OK.
If Apple bough Italy they wouldn't have enough money to make it work
Italy needs two trillions/year to go on, Apple only owns a fraction of that to spend.
That's why it is a worthless comparison.
A more apt comparison is
Apple is valued 2T at 260 billions of revenues in 2019
The total amount of Italian wealth is around 11T at ~2T year of output
GDP is an aggregated annual "earning", a market capitalization is the value of all the outstanding shares of an entity, not a periodic earning.
A more meaningful comparison would be Apple's annual earnings ($260B, still quite a lot of money) vs a country's GDP, or Apple's market cap ($2T) vs the value of an entire country, rather than their latest GDP.
"They're worth $2T, but they didn't make $2T this year, they made $260B".
Italy, No