Games became worse because they started being made as mass-market entertainment with absurdly large budgets catering to the lowest common denominator. And this process was well underway even back in the era of console exclusivity (see - PS1 vs PS2)
It is not a coincidence that games became worse and worse as console manufacturers began competing with one another less, and everything just started going to PC instead. The medium was at its best when all of the consoles were viable choices and had distinct identities and options. Do not listen to a man who plays World of Warcraft for a living about video games.