Score =/= quality.

I don't disagree with that, either ;)

I've played GT1, GT2, GT4, GT5: Prologue, GT5, GT6, FM2, FM3, FM4, FM5 (just for a short while at GameStop).

I've driven a Corvette Z06, Audi S4, '13 Camaro SS, 11' Chrysler 300C (I currently own), my uncle's old modified '68 Mustang fastback, my other uncle's modified 1988 Trans Am (several donuts were made that day), and a BMW 335i.

You don't really need to drive fast cars though, you just need to have driven a car fast/competitively to know that GT is more accurate to real life when it comes to car physics. Forza is getting better though, but they could use more time per game I think.

I have GT5 and owned FM4. Though Forza was fun for the first few hours, after that I noticed certain driving flaws that I just got irritated. GT5 also has it flaws but at least driving was much better, GT6 has even better handling of cars however not all the content has the same quality (mostly graphics) but it still has much more content than any racegame.

Overall presentation is the only thing forza wins but it lacks content and some things look far better in GT6 (premium car models and tracks, lighting), Driving simulation wins GT6 over any racegame ever on console.

Dunno them, are they aimed at the same target audience?

If something sells more over the long term it generally means its a quality product, because it does its job right and has good word of mouth with the target audience. Demon's Souls to Dark Souls would be a great example in the videogame industry. As would Final Fantasy XIII to XIII-2 and Lightning Returns.

Gran Turismo generally sells 10 Million plus over the long term because its a high quality product. Yeah, it opens to high numbers based on hype alone but you have to look at the legs and consistency.

People genuinely dont care that some cars look like updated PS2 models because the core gameplay is the best available. People want to rally. People want to race in the rain at night in a Mini. People continue to jump onto GT in gigantic numbers because its the best on the market for the target audience.

sorry youre wrong.
NFS shift for ios is the highest rated this gen at 94/100. That means its better because metacritic said so.

How could you not know who Kafka was?!

What you're proving here is that sales might be a factor that points out to the quality of the game, but it is not the necessary factor for it. I never argued against this, I merely said that sales =/= quality; just like score =/= quality. Besides, the Souls example isn't that good, since Dark went multiplatform. Are you telling me Gran Turismo wouldn't sell even more if it went multiplatform?

Youre not getting the Souls game example. Obviously going multiplat opened the game up to more people over the long run. Im talking about the opening/total sales of Demon's Souls to the opening of Dark Souls.

Demon's Souls sold 39,000 units Week 1 and less than 100k in Japan in 10 Weeks. Nobody thought it was a real success because it simply didnt sell a lot. The game went on to sell 345,000 units and became a hit due to the legs. These legs came from brilliant word of mouth and Dark Souls opened up to fantastic numbers there, outselling Demon's Souls on PS3 within a Month and going on to sell over 500,000 units.

Demon's Souls released in America a few Months after JP to a modest 50,000 units. It dropped quite heavily the week after and after that maintaned a steady 10-15k for the next 8 Weeks in the Holiday season. In 2009 the game sold 213,000 units. In 2010 the game sold 250,000 units. In 2011, the Year that Dark Souls was released, the game sold 265,000 units. The game had fantastic legs based on word of mouth because it was such a great game.

Dark Souls sold 266,000 copies in 10 Weeks in the USA on PS3 alone. Add in the 360 sales and the game sold 440,000 units in 10 Weeks in the USA. A huge increase in sales and more importantly for Bamco, profits.

Demon's Souls released in Europe quite a while later, mainly due to people begging for the damn thing to be released. As this was Europe the game didnt do as well as in the Stated and in Japan, though the game did eventually sell 250,000 units here after opening up to a relatively low 30,000 units.

Dark Souls, sales combined, sold 215,000 units in 10 Weeks. 

Legs on the original followed by a great opening on the next game.

When a videogame sells incredibly well after a modest opening, its a damn good game for the target audience despite what any "pro" reviews say (even though Demon's Souls was reviewed well). Word of mouth has sold the title. The target audience needs to be taken into account. Its what counts when you talk about sales and quality. The consumer isnt as stupid as the "pro" reviewer thinks and the "pro" reviewers in this industry are in large no more reliable than or no better than me or you. ethomaz or selnor. Pezus or JayWood. 

Sales perfomance is the biggest and most important factor when determining what is and isnt a quality title/product. Not a review score. Certainly not a bunch of review scores put together on a website. You just dont compare everything to the sales of Mario, Call of Duty or GTA. You compare it to things it competes against. You compare it to other stuff in the genre/sub-genre. You compare it to titles in the same series.

Sales is a terrible way to judge quality.  Avatar and Titanic are the highest grossing movies at the box office but neither movie are anyway near worthy of being mentioned in a top 100 movies of all time list.  Also the Dallas Cowboys generate the most revenue when it comes to NFL teams but the actual team has been one of the biggest jokes in the NFL for at least 15 years.

How does this game compare to GT5? I actually liked that game.