The graphics versus gameplay argument is a red herring, it's used by, mostly, Nintendo gamer's when faced with criticism over Nintendo-based titles looking not so great as a result of Nintendo's ongoing trend to release consoles at the lower end of the performance scale, sometimes significantly so, the whole "yeah but gameplay is more important", it's then bait and switched on the odd occasion where something on Nintendo is released with actually half decent graphics, and suddenly their console of choice having "better graphics" suddenly matters more.
Take for example the WiiU version of need for speed, it was ever so slightly better than the xbox 360 and PS3 versions, Nintendo fans took this as gospel truth to mean that not only did that particular title look better, but that it was also proof that the WiiU was a more powerful console.
When the actual truth is, you can and do get both great gameplay and great graphics in many games, great graphics do an awesome job of boosting immersion and by extension, making the gameplay more enjoyable, the notion that most games these days focus more on graphics than they do on gameplay while potentially true in a handful of cases, is false for the rest of the industry.
People just want to build things that are as nice to look at as they are to play, when a console doesn't have the power to do that, you ultimately find people playing the gameplay > graphics card, because in truth, what options do they have?
So the answer to your thread topic is simply: Never
Nobody builds something pretty and intentionally butchers gameplay, hell nobody sets out to make a game that isn't fun to play at all, some just end up good, and some just end up bad, regardless of how good or bad the graphics are.
