Why are there 3 separate listings for the same genre?

The most important issue when making a listing for a genre is trying to separate apples from oranges. The genre subject to this blog, heist movies is a sub genre of crime movies. Even though it is already a sub genre, if you put all of them in same listing, you will be ending up with this apples-oranges problem. Where to put a great heist movie intended to be a comedy, sometimes a kind of fantasy among the first class job serious heist movies? Or how can you decide if a heist movie like Inside Man is better than a Dog Day Afternoon, while the second one's concerns are completely different? Does grifting / fraud movies fall to the genre? Can we count the movies for this listing which are simply about stealing but not organized heist? What about the movies whose main action is burglary? And the ones is about trying to get a ransom by committing a kidnapping, but very well organized and told? What about the movies where the stealing action never takes place, but the characters are after already stolen (or lost while stealing) loot?

That's why I tried to divide the genre into 3 main categories to be fair at least to my cinema view. And, of course, I applied my own criteria to judge what movie falls into what group. And even that method was sometimes not enough, so I sub-grouped them with the type of the theft committed. At the end I could call all those movies as 'theft movies' without being have to skip any of them without mentioning.

First group is called 'Pure Theft Movies'. I could call them as '100% Robbery / Heist Movies', too but since not all the movies can be counted for the genre is about heist, some of them grifting, some of them burglary, so I preferred the first one.

To me, 'Pure Theft Movies' are the movies basically:

a.Their plots are serious
and
b. Can happen in real life although sometimes they are pretty fantasy like
and
c. And their story concentrates on -generally organized- theft, where we see at least one of first two acts in a satisfactory dose.
(Act 1: Introduction/Preparation, Act 2: Stealing, Act 3: Aftermath)


Second group is Caper Movies. They are the movies:


a. No matter what acts of the movies is told/presented in what dose, they are intended to be a comedy in first place.
and
b. Their plots are humorous and what happens in the movie can't happen in real life or too coincidental to happen.


And the third group is called 'Alternative Theft Movies'. Meaning that:

a. Although the movie is most of time absolutely about theft and thieves, it concentrates other matters more than the theft act, therefore falls other genres like drama, adventure, biography before it falls to heist genre. 
or
b. Concentrates the thieves more than the theft, so most of the time, they are character studies or even sometimes biographies.
or
c. Separate themselves from other heist / theft movies by having radically different nature or a different grammar.
or
d. Solely concentrates on Act 1 (Preparation) or solely on Act 3 (Aftermath) or concentrates one of these acts much more than other other two acts.



In that point of view, although some movies are considered as caper (like The Sting, Ocean's Eleven) in general, to me they were Pure Theft Movies. Or i.e. although the story of Inception is completely fantasy, can't happen in real life, because of the grammar and coding of the movie, it is a Pure Theft Movie for me. (I could categorize it as Alternative Theft Movies, as well, though,I quite hesitated to decide). Or although Quick Change is a comedy heist, since it is as organized as the serious heist movies, and a heist could happen in real life, it isn't a caper movie in my opinion. If you are interested to know why I categorized each movie in what category, see the post called 'Coding' where I provided a link at the upper left side of the blog. But I should warn you, it may contain some spoilers.

If there will be some feedback from you with your argument, they will absolutely might change these categorization.