I am not against spotters and occasionally use them when going for a new PR single, but I think people become too reliant on others.
When I trained for competition, I was tuned into my body and knew exactly what I could do. I set my mind before I did a set and NEVER missed. If I had doubts I dropped the weight and did more reps or moved to the next exercise. Lifting to failure, doesn't mean that you NEED to fail in the middle of a rep, just that you have no more juice left after your last completed rep.