bull. if going to failure is ever advantagous, which it may be every now and then, it would apply to every muscle, not selectively.
It would, except for a few things. First, you obviously have to consider the physical system as a whole. A set done to failure on a rear delt machine is a lot less stressful than a to-failure set on squats or deads. Obviously.
You have to consider what the typical last possible rep on a set of an exercise looks like. On some movements you can strain for a few seconds whereas others you fail at quickly. The longer you can strain the more "damage" is being done to the muscle, not to mention nervous system. And what does the eccentric component of a movement look like? You mentioned "Olympic powerlifters". Olympic lifters actually often train very close to max for multiple sets, with high frequency. How can they do this? There is no eccentric component to the Olympic lifts! Olympic lifts are less stressful on the system and individual muscles than the powerlifts - where max lifts are often sloow and strained, plus you have heavy eccentric loading. A snatch to failure is lot different than a deadlift to failure!
There's a lot of close-to-failure training done by powerlifters too. A few have stressed that you should never fail in training, mostly due to psychological factors. But many/most powerlifters, for example the "Westside" guys, go to failure frequently, tons and tons of missed lifts in training.
Then we have the whole "muscle damage" theory which is often equated with the DOMS. The research, from memory, is a bit conflicting. Some data says there's no structural damage done despite DOMS, for example. That the DOMS may be due to some 'chemical leakage' which stimulates pain receptors. Paraphrasing, one study said that DOMS could simply be seen a sign of adaptation happening, not muscle damage as such.
IMO you'll not get as strong as possible without ever going to failure, much less 2-3 reps shy. And you'll never get as strong as possible by always going to failure.
You have to consider the person doing the program, the movement selection, and you have to consider the program as a whole.
There is no magic hypertrophy trigger in the last rep. But there is no overtraining/muscle damage trigger either. It depends!
