I can't speak to when the game officially began it, though based on other posters' quotes and notes it was earlier than I ever thought.
For me it was some time ago, as it always seemed to me that a Ranger was intended to meet the intersection of "Fighter & Thief (with a wilderness theme/bent)."
When looking at the classes and what they are primarily or "most" reliant on, while 1e -and to an extent 2e - tried to focus the Ranger in on "Fighter" a.k.a. someone who fights/is all about the combat, their general class abilities set (even before the skills rules changed/expanded) seemed to indicate otherwise. Aside from the increased damage to [poorly] so-called "giant class humanoids", a ranger was about using Skills. Skills that other classes didn't - in early editions - have access to.
The reliance on "Skills" has been the ballywick of the Thief/Rogue class(es) always. Tracking. Nature/flora/fauna lore. Animal Handling (though originally treated as some kind of mystical connection, "Empathy" for calming beasts). What we would now refer to as "Stealth" and "Perception." Movement (another hallmark typically attributed to Roguish classes) through difficult terrain. Even their damage bonuses were fluffed as a special "knowledge/training" against specific creatures/foes. Whether or not one wants to get into the whole "Forgotten lore/divination magics" thing, the Ranger class abilities are a suite of specialized skills...not "Combat" abilities, as a Fighter/warrior class would be built upon.
So, it is not a very long walk or require a lot of twisting, to view the Ranger as a "wilderness rogue" who is also quite good at "warrioring." As opposed to the Ranger as a "wilderness warrior" who is also quite good at "rogue-ing."
Another way to look at it, if one likes to catalogue their classes, if:
--Barbarian is to Fighter.
--Druid is to Cleric.
--Sorcerer (arguably) is to Wizard.
...then it seems quite natural/automatic for...
--Ranger is to Thief/Rogue.
So, yeah. Long story not-so-short, I have no problem (and haven't for decades) envisioning the Ranger as a sub-set/specialized type of "Rogue" class...leaning "warrior," sure. Better armor than thieves. Some better combat options than thieves. But ultimately, a class that relies on "skills" not "weapons/armor/combat."