I am, in fact, of the opinion, that sales figures that are very high will cause the game to get worse as the developer starts to get lazy. When you get to the point that people will buy a turd in a box just because of the title of the game, that's when whole franchises go downhill.
I've been lurking here off and on poking in to see if there was anything worth oogling in here or remarking on, so it's sad that it's for this reason.
This is a really tired argument which is almost universally untrue. Bringing up one or two anecdotes of a game which isn't wonderful selling well is a fallacy, and it certainly doesn't make you wise for mentioning them. Most games which aren't much good die quickly. With darn few exceptions, game sales are the prime barometer of how good a game is, because reviews can be anything. And game companies aren't selling to reviewers, but gamers.
I sincerely doubt Luminis will hope that Forza 4 sells poorly so that this will make Microsoft hungrier for an even better Forza 5, or fans will mention that sales figures for F4 are meaningless. Were they for Forza 3...?
Likewise, people act like the public bought GT5 with no exposure to ANY content at all, just blindly. Ignoring the massive penetration of Prologue in the market. Or the presence of hundreds of thousands of GT5 kiosks, or the sharing of the game with friends. I've read a number of posts here of those scared off from buying the game, only to find that when they played it at a friend's place, their eyes were opened to how overstated all the criticism is. I know some of you find GT5 to be completely messed up, well fine. But then you still assume that everyone feels the same way you do, as if most of the posts on the board from the several hundred to thousand visitors to the boards every day were rants about how shoddy the game is. While in fact, it's the exact opposite. Just reading thread titles, you'd hardly know there were any malcontents here to speak of.
Oh, and let's pretend that Forza has had no issues over the years, made no broken promises, didn't port any content from previous versions, outsourcing caused no issues, yadda yadda. Let's ignore the small revolution that happened when the many promises for F2 went by the wayside: everything from F1, 12 car races off and online, a dramatic improvement in everything. Turn(10) a blind eye to the violent bots, or messed up liveries when taking a car out for just a photoshoot would cause random vinyls to shift around, or that adding elements to some car surfaces caused dreadful glitches, or that models were just wrong - still - having the very same issues from F1, or scrolling through your garage could crash the game - or just painting a car too long, or that getting disconnected from the Auction House could get you permabanned from Live, or that there were periodic physics patches as cars were exploited on leaderboards or online races, or that you could set up a car completely wrong and still race competitively, or that making an AWD conversion improved every car's performance drastically... etc.
And some of this is still carried over to F3. It seems T10 doesn't know what to do about the AWD issue, or how to keep certain cars from being exploited unfairly, or how to make car models without bugs mucking up liveries, or even how to make the file system work as well as an old 486 PC. Have more than a hundred pics, decals, liveries... anything, and the 360 bogs horribly. Forza fans will make fun of some Gran Turismo physics issues but give a pass to easy drifting or the pinball behavior of cars in high speed collisions. I had a lot of fun when I was bored making cars bounce off the "ceiling" of the atmosphere. And was it smart to gimp the online system from what was working pretty well in F2? Have any of you tried to share pics using the brain dead system T10 created, or noticed that the only good pics are from people who buy capture cards or spend a lot of quality time with them in an art program?
So sure, if all you want to do is tear around a track and buy stuff from the online stores, Forza is a blast. Of course unless you're in a club, you'd better have an AWD car to be competitive. But if you want to actually use the many other community friendly things which should be a blessing, like car painting and photo shooting, you might find an increasingly large bald spot appearing on your head, and a lot of time wasted.
It's quite appalling sometimes to hear terms like fanboy applied to GT fans, while discussions and criticism of these two games is mostly one sided.