No, I doubt that. I already know that modes are missing and online is a factor. But, thats only a small factor in sales. Most people who buy games out their do not read reviews so they dont actually know that its missing modes. They just buy the games. Think about how it was before the Internet was invented. There was only Magazines which not many people would actually buy. How did companies sell? With Ads, so if you cannot market the product appropriately you will not sell.
A perfect example is Red Steel. It has a 63/100 at metacritic. Basically the game sucked. Some people liked it but most people hated it. But it sells a Million copies! Zack & Wiki gets a 87/100. Thats 24 points higher on average. I dont think Zack & Wiki even sold 500,000 copies. I forgot the number but its really low. Mario Party 8! 62/100... Sells 2.89 copies... Why? Because Nintendo advertised Red Steel and Mario Party 8. So yes... Shitty games do sell if you actually have marketing skills.