Biggest grossing movie of all time

https://m.imdb.com/title/tt0031381/releaseinfo

It’s been released about 10 times in the USA alone. Right now (12/25/2021), the movie is still airing in some theaters in Manhattan, such as IPIC Theaters.

In its initial run (~1939-1943ish), the movie pulled about $500 million adjusted for inflation. The many re-releases over the decades gave the film an extra $2.8 billion.

I don't believe I do personally but - two part answer:
It does bug me when studios make their unadjusted claims which are then unthinkingly accepted and echoed.
Also, it's a little bit interesting watching how successful, or not, the big money franchise films are working out.

This movie is much more than money making.

"I've never seen any disclaimers on those online inflation calculators saying
"no way to do it accurately; there are far too many variables""

Well now you know.

"Sure its not an exact science but I would think it would be fairly easy to get a very very accurate picture , by looking at the prices of gold , houses , bread , wine ... whatever
and wages."

Not even close. As one example, did you know that the average price of gasoline was slightly cheaper in 1999 than it was in 1980?

https://www.creditdonkey.com/gas-price-history.html

But this .gov inflation calculator tells you that $1 in January 1980 = $2.16 in December 1999:

https://data.bls.gov/cgi-bin/cpicalc.pl?cost1=1&year1=198001&year2=199912

Look at bicycles. Even though the price of high quality ones is through the roof now, the price of entry level ones is still around $100 or less, the same as it has been for my whole life (nearly 50 years).

Some things get cheaper, some things get more expensive, and some things stay about the same price. On top of that, in order to come up with an accurate inflation calculator, you would have to somehow be able to assign a level of importance to everything that people buy, and that alone makes the number of variables go well into the millions, not that there's a credible way of assigning levels of importance to begin with.

"..much more easily than trying to work out how many cine tickets got sold"

It is way easier to come up with a reasonably accurate estimate of the number of tickets sold than it is to come up with anything even remotely resembling accuracy from an "inflation calculator." All you need to do is divide the movie's actual gross by the average or typical price of a ticket at the time.