To me, Newsweek was always only a Time-lite, but of course I'm talking about Time when it was great, run by Henry Luce. As a child, I used to collect old editions of Time magazine, building up a near-complete set of them 1923-1967 (the editions after 1967 were not worth anything but scraping one's butt on them), and so I'm pretty familiar with the magazine, once an Institution. I also collected old Newsweek magazines, but not nearly as many.
The extinction of the weekly newsmagazine was perhaps inevitable, given changes in technology and communication, but I bet both Time and Newsweek could've staved off the Grim Reaper for at least another 20 years, had they adhered to the standards of Henry Luce, relaying the news rather than propagating viewpoints not really popular with the public.
I haven't even looked at a Time magazine the past three years, when il Duce Bo began being a common cover-figure--39 times in 52 weeks, or something like that. It was too too too much; even Franklin Roosevelt and Ronald Reagan, not to mention other prominent world leaders, appeared on the cover that much.
Overkill.
Actually, my final disillusionment with Time dates from 1990, when the magazine named Mikhail Gorbachev as "Man of the Decade," rather than someone else who, uh, did a great deal more than the Soviet dictator. It was obvious why the magazine selected Gorbachev, because the alternative was someone who did not represent the liberal elites' point of view.
And so that's what's killing the weekly newsmagazines perhaps 20 years sooner than they have to go; their strident advocacy of political views not really popular with the general public. There's a place in the "market" for such magazines--the Nation being a good example--and while such magazines may flourish and prosper, they also lack the big circulation numbers.
And the problem with both Time and Newsweek is that the market was already glutted with Bo fanzines; they were offering nothing new or different, just the same stuff as all these others.