I disagree to a certain extent.
There are different degrees of failure.
For example, if I put a gun to your head and said I'd kill you if you didn't do one more rep, you'd bust out one more rep, I promise.
Lifting to failure is not "easy". Your goal should be to maximize each workout and get into a mental zone where you literally anihilate the muscle and not the weight. Multiply that by 1,000 by training hard and being consistant.. the muscle will grow.
Also, with legs for example, when doing leg extensions there's build up of lactic acid that makes the muscle burn when you contract. You can get to a point where you can't do anymore but if you truly put your mind in the muscle or if Arnold walked in the room, you could keep going.
There's a story about Franco not being able to squat his normal weight for some reason while these kids from his homeland cheered him on. Franco left, came back 5 minutes later and hit an all new personal best.
I think your going to get big and gain mass from just working hard and being consistent. It's better to have 20 workouts a week with a few not being as-great as the others as opposed to just having 12 or 13 and skipping the ones where you didn't feel like 100%. Hard work will get you to your goals....
I say just concentrate on working hard and being consistent, then practice pushing your perception of failure, sometimes you can do more, sometimes you can't, just keep at it and it'll grow anyway.