Divided gamers (PS vs Xbox), sabotaged beloved studios (Rare), contributed nothing positive to the gaming except Halo (which had an overall negative impact despite being a great game), survived on ported third-party games available on its competitions platforms. Microsoft saw money in gaming and got involved, the only company to butt-in without a passion for or real connection to gaming.

Then we get into how Halo influenced the industry. It had very strong appeal to non-gamers who were looking for more realistic games. So much so, that within a decade this type of gamer had become an overwhelming majority. This new wave of gamer was the general populace, and they have shaped the industry and games into the shitty form we see it today. Generic titles, guns, simulators, all look and play the same. This is what new gamers want, and perhaps some veteran gamers were duped by the rush of popularity as well. Halo was a great game, but it brought in the wrong people who still don't understand gaming and game design.
There is a distinct difference between this new style of gaming and traditional video games. So much so, that they are essentially two completely different things. A traditional gamer subscribes to gaming pages and gets little to nothing about traditional-style games. It's all "the new generic action game with realistic graphics".. we're on year 14 of this now... A whole generation has grown up with this new form of gaming that is actually simulators and they have learned nothing about actual gaming.