There's been a big shift in brewing consciousness in the last few years where many of us believe that yeast is a good thing, and besides just fermenting the beer, that they are fastidious creatures who go back and clean up any by products created by themselves during fermentation, which may lead to off flavors.Rather than the yeast being the cause of off flavors, it is now looked at by many of us, that they will if left alone actually remove those off flavors, and make for clearer and cleaner tasting beers.You'll find that a great many folks, maybe even the majority on here these days, leave their beers in primary for 3-4 weeks, skipping secondary. Many of us even dry hop in primary, and only rack to secondary if we are adding oak or fruit, or had fruit in the boil or primary and left lots of trub behind.
Even John Palmer talks about this in How To Brew:
"Leaving an ale beer in the primary fermentor for a total of 2-3 weeks (instead of just the one week most canned kits recommend), will provide time for the conditioning reactions and improve the beer. This extra time will also let more sediment settle out before bottling, resulting in a clearer beer and easier pouring. And, three weeks in the primary fermentor is usually not enough time for off-flavors to occur."
This is where the most up to date brewing wisdom and ideas can be found...In fact a lot of stuff has been started on here, and made it into byo or zymurgy or podcasts...in fact BYO DID a piece on no secondary/long primary, along with the BASIC BREWING PODCAST and even they said that there were no issues/harm with doing it and in some beers it did actually improve the flavor and clarity. And I believe that really WAS influenced by the discussion we have had for the last couple years on here.
Kevin Wright - Third Space Brewing