It's sort of a logical explanation.
The Fallout series is attracting idiots because the games attracting them are being released by Bethesda and Bethesda alone.
So the real question is: why is Bethesda's Fallout attracting so many idiots? And the answer is, quite simply: because Bethesda caters for idiots.
I'm new to the forum, so I may as well provide some background: my first "RPG" was Final Fantasy IX. I played a few Final Fantasy games, until I got my current computer. My first "RPG" on this computer was Skyrim. I put 350 hours into it, all in one playthrough, never had restartitis.
I don't remember the sequence of events correctly which made me find Fallout 3. I simply don't. All I remember is getting Fallout 3, playing it, enjoying it, etc. Then I discovered New Vegas, which I was reluctant to get because of muh post-apocalyptic atmosphere Fallout 3 had.
Played New Vegas, loved it. Eventually, I was at a crossroad, one of those crossroads that doesn't exist anywhere but in your mind: should I give my love to Fallout 3, because of muh atmosphere? Or should I give my love to New Vegas, because of muh gun variety?
It's been a year since that already. My heart made a decision: it was New Vegas. For the guns. But later on, I realized what was actually that got about the game: everything that Fallout 3 never was. A much better RPG. And I've never looked back. New Vegas is a much, much better game, which suffers sadly from the small time given to Obsidian, but otherwise, a fantastic game.
Anyhow. I bring this up because I want to introduce myself, but moreover, because I mentioned three very important things, in order:
1) A lot of Fallout players may be playing Bethesda's Fallout solely because it is BETHESDA. I got Fallout 3 after playing Skyrim, read it was similar to it, and good enough, Skyrim is an updated Fallout 3, in a fantasy setting.
2) A lot of Fallout players may be playing Bethesda's Fallout because of muh atmosphere. Which, after I thought of it, didn't make sense. I eventually got around to seeing videos of the old Fallouts, and the truth is Fallout 1 & 2 are the only TRUE Fallouts. And the reason I say TRUE Fallouts is not only because they were the originals, but moreover, because Fallout: New Vegas had to deal with shit that they didn't want to deal because of Bethesda. Who knows how different New Vegas would have been, had Obsidian started from scratch with the license on their hands, and no previous Fallout 3... Fallout 1 & 2's atmosphere may not be to everyone's tastes, but for the sole reason of being the originals, it is the true Fallout atmosphere: that of a world that is being rebuilt.
3) A lot of Fallout players may be playing Bethesda's Fallout... because it is easy. Because it is simple. Because it is Call of Duty. I don't like people automatically dissing games as "Call of Duties", since I actually enjoyed Modern Warfare 3 a lot. But Call of Duty is Call of Duty, and Fallout is Fallout, and above everything else, Fallout is an RPG, something which Bethesda's Fallouts, by my standards, aren't.
In few words:
1) Current Fallouts are Bethesda's, and people like Bethesda.
2) Current Fallouts have that post-apocalyptic vibe people like.
3) Current Fallouts have been casualized, a lot.
Like I said: my first "RPG" experience was Final Fantasy IX, which by no means is an RPG like Fallout 1 and 2 were. And what I expected from Skyrim, at the time, was one of those complicated RPGs I always heard about. And it wasn't. At all. It was a very simple game to understand, and to beat. Now put it in a post-apocalyptic setting with guns, and it's easy to see why people like it so much, and it is even easier to see why people who have played the originals are frustrated about it.