Hubris, the downfall of many a gaming companies.
Sony-We'll introduce a $500-600 console, people'll buy it because we just had one of the most successful consoles of all time. (They ended up coming back and effectively tying 2nd place for units sold but lost a boat load of money over the last 7 years)
Nintendo-People love our handhelds, we'll make this one $250. (They've recovered mostly but lost a lot of money in the process)
EA-Everything has to make money for us; online passes, microtransactions, etc. "WE NEED MORE MONEY" (CEO is out, stock down to $17 from the $70 it was at in 2005) Lest we forget Sim City...
THQ-We make good games but we can be bigger, we've gotta make tablets and people will buy them! We all know how that went...
Sega-Who cares if keep coming out with new add-ons and consoles every year or two, we're Sega, people love us and they'll keep buying our stuff no matter what...
Clearly Microsoft has the same, "People will buy whatever we make" mentality going into this generation. We're not just talking about this online requirement but the general sentiment coming out of GDC seems to be that Microsoft ain't doing dick, and getting downright hostile, about geting developers involved in their new console. There seems to be an outright arrogance coming from Microsoft regarding their new console and the way it's going right now the train doesn't appear to be getting any closer to getting back on track.