what do you think are the reasons for the contining popularity in furniture that is very reminiscet of the sixties design?  

I apologize if your question...
I apologize if your question was sincere, but it did sound smug. To answer you, I did use the table and 4 tulip chairs covered in red fake something plastic, non swiveling since I had 2 small children at the time. The 3 chewing gum wads they stuck under the table are still there, hard as a rock. Ten years later I sold the 4 chairs, pretty shabby by now, to a used furniture store in MtVernon NY, but kept the table, for some unknown reason,(Knoll was just another furniture maker to me then)put the table "away", to be replaced by a large glass topped Stainless steel Parsons table from Bloomingdales outlet. Forward to about 6 yrs ago, when I inadvertantly discovered that I now owned a "classic". BTW, cant tell u/how many times I have kicked myself for selling those 4 chairs, think I got $50 or $100 for them. A daughter is getting married or moving in, whatever, and she will buy 4 swivel Knoll tulip chairs covered in Red fabric. I may just "lend" her the table....

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A stainless Parsons table is also a classic table type, you have a good eye for style...

Continuing popularity...sixties design
Somebody mentioned "smiling" qualities, which imho can't be discounted in these bleak, "Bladerunner" times--I'd like to advance the thought that the ideal of the period (for me, about 1947 to 1967) was a blend of order and playfulness. Eva Zeisel in the Nov. 13 '05 New York Times: "The Bauhaus was too cold." And see _The New Look: Design in the Fifties_, Lesley Jackson, Manchester City Art Galleries, 1991, p.21-23: "The Modern movement emphasized the primacy of function, and the need for form to follow function. The New Look introduced the idea that function need not be threatened by a more adventurous expression of form, and indeed that an object's function extends beyond the parameters of its measurable usefulness... Eva Zeisel... argued: '... For every use and for every production process there are innumerable equally attractive possibilities.' ...The New Look inherited from the Modern movement a commitment to purity of form, clarity of outline and the paring away of superfluous details, but it acknowledged the expressive potential of the line itself, which could be used more freely and creatively."

I think alot of it has to do...
I think alot of it has to do with the younger generation taking an interest in styles from the 50s-60s. Alot of people my age(20-30s) have gotten rather tired of the 'PotteryBarnish' style furniture that many of us grew up with. IMHO, this furniture is rather boring and everyone bought it to try to 'fit in' to the typical decor of the times. I just think many people have become tired of the usual furniture that just doesn't stand out so they turned to a time period where the furniture really stood out and had a personality all its own. People who like 50s-60s modern style furnishings are usually people who look for art in more than just paintings on the wall. They want their furniture to not only be functional but to be art too...which was something that was gotten away from in the last half century and is starting to become popular again.

I like
Eva Zeisel's comment, above, about freedom of line and the possibility of a more expressive minimalism. . .

ZEISEL
her work has joy, wit, style, how many people have a one person show at the Lourve...