The .308 is my gun of choice! It will be around long after all of us here are dead and buried! The marketing and popularity of the newer WSM's and magnumitis have pushed the popularity of many other cartridges like the .308 back a bit, but it will never kill them!
I would not say that the WSM's are "not needed." Some of them are great cartridges, and they have boosted sales for the gun industry! But, they are something that I could have lived without! After the "magnumitis" trend fades, some of the better WSM's will live, others will die but, the old standards will still be here too! The Anti's have a much better chance of taking all of our guns away, than of the .308, 30-06, and 30-30's dying!