that's not strictly true. it's the manual "as revised". each time a tsb is issued, it's what's in the tsb that prevails. just like a service pack or software update for your computer.
if you don't want to follow the manual's service schedule, do oil analysis. all this blind gut stuff is utterly retarded. so is never checking the simple stuff that can be easily checked come to that, and looking inside the rocker cover is hardly difficult to do.
as for toyota sludging, it wasn't /every/ toyota that did it, just a very small subset of users that would literally drive around the block, then stop. repeatedly. if the oil never reached operating temperature but was constantly loaded with condensates, i'm sure pretty much any car would be susceptible. and you then have to ask, to what degree does the engineer have to anticipate statistical outliers?