It is possible that the quantity of the beer being made effects the amount of off flavors generated by autolysis. That 5-10 gallons is just not enough to have significantly over threshold levels. This is why home brewers can leave their yeast on the sediment for weeks, while in the lab or commercial setting this has been less than helpful. It could also be that the yeast being used today are so much purer than before. It could be that home brew, especially in the U.S., has higher hop rates which mask the autolysis taste.
The use of fining agents and leaving break material in the kettle, or straining it, could significantly reduce off flavors from trub. Maybe autolysis was not the problem, but yeast feeding on hot break material. The pervasive use of irish moss, or racking beer off the break material into the fermenter, might allow for long primary fermentations.
All these variables are part of the problem with resolving this issue. We all probably do some things a bit different. Some primary in plastic, or better bottles, or glass. Some use hop backs, some do this or that. So, when someone says they leave their beer in the primary and it tastes fine, it is hard to relate that to any other brewer.
It is always hard to say since nobody splits worts and does controlled triple tastings. Maybe your beer would have scored 42, if you had moved it off the trub. Who knows. I've seen Papazian reference a study done in BYO magazine where they split a wort and submitted it to judges who couldn't tell the difference. But I can't find anything online, and maybe certain styles of beer could be discerned better.
Looking through award winning recipes, most use secondary fermenters. But not all do. So, maybe you can conclude that fine beer can be made without the extra step, but it is easier to make better beer using a secondary.
I have just gotten back into brewing recently, after about 10 years. 10 years ago, every serious brewer used a secondary. So, I've had to catch up quick on this controversy. From what I can tell, it is important to leave the hot break material in the brew kettle. But the cold break material really doesn't effect things and yeast just don't autolyse that fast, at least in home brewing.