TLoU doesn't count?
It had 7M copies sold on PS3 alone on its first year basicallyk like Horizon Zero Dawn) with the PS4 already existing for the most part of that time (driving the userbase away for the PS4), and it has now reached 17M copies sold, the PS4 version came after just that one year moving the original legs for it (like a GOTY edition).
It's not like it sold 1or 2 milion more copies of people who double dipped, TLoU was still very fresh and gaining traction, it was the game legs acting up.
It sold 10M more copies after it moved to PS4 alone.
No matter how you look at it, it counts, from any angle.
TLoU is the most successful exclusive game ever to not come from Nintendo.
A huge amount of people double dipped with the last of us. It's one of those games that almost everyone I know that bought it on ps3 bought it again on ps4. I'm sure it would be over 10 million if all it's sales were on just one console. But it wouldn't be close to 17 million. Are we going to say Mario kart 8 has sold over 23 million copies. How many copies of last of us were sold at full price? the game is currently $18 on Amazon.
Mario Kart got revived on the Switch, it was already 3 years on the market when it came, though that doesn't take any credit away from it, if it was good enough to interest the new audience on Switch and become successful on both platforms, well, that's great. It's not the same thing, tho.
The Last of Us moved its audience to the PS4, it released June 2013 if I recall it right, and the PS4 released November that year to steal PS3 thunder, the game didn't have half a year and its console was already not the focus anymore. It still sold 7m copies on its first year there regardless, in just one year being most of this time on a platform from last generation.
Then with that one year came the PS4 version and completely moved its audience from PS3 to there.
We are talking about a very different scenario here, TLoU legs moved platforms, exactly like GTAV, most of its potential sales moved platforms and picked the game there.
About your personal experience with people double dipping, mine is that neither me nor none of my friends that utterly loved it have got it again on the PS4, none. That's just it, personal experiences.
About the game price... that doesn't matter in the slightest, we are talking about sales here, and even then, PlayStation games have the healthy price drop as any other non-Nintendo games, it's absolutely normal for an almost 6 years old game to be a lot cheaper today than on release.
About its 17m sales... yes it would not reach it without the PS4, but that doesn't take away any of the game success from it.
If it was hold to release on PS4 day 1 as Nintendo did with Zelda, maybe it could have sold that, being a fresh game on the new platform with a stellar reception, instead of a game a lot of people had already played last gen. Did Zelda ever sell this well being on a single platform? No. So should I take that away from it because its also on the Wii U? No.
No matter how you look at it, TLoU sales naturally moved from systems, cutting short any of its sales because of that is doing the game a massive injustice.