I had to learn this lesson the hard way - much like everyone else does.
In training for strength, 100% of us base our progress on the big lifts; whether it's a rep record or a 1RM. This is fine and these movements are the Meat AND the Potatoes, so to speak. However, getting these movements stronger isn't just about doing those particular movements. That works fine in only three instances:
1. Training is GPP - meaning that training is a means to an end. For example, lifting weights is GPP for all athletes. This doesn't mean athletes should ONLY do the big lifts. It means that they are a means to an end.
2. You are training "just because". For example, if you were a 40 year old dude and just need to get into shape/get stronger and not interested in putting a ton of weight on the bar. So you are just lifting to have a general better life.
3. You are perfectly suited (physically/mentally) to do the main lifts. This is rare. Also, this works for people that are just born cock-strong.
The rest of us, the vast majority of people in the world, can't do just the main lifts to get strong on them. You can for awhile and it may work initially but we need to raise our entire base level of fitness and strength. So for example one of my good friends (who is average guy) measured his upper body "base" by supersetting dips and chin ups for 10 sets of 10 reps with a 45lbs plate. This was his base of upper body strength and as long as he was able to do this on the regular, his bench was pretty awesome. As you can imagine, he was a strong dude and had been training a long time.
Now understand that he didn't do this every single day/workout - and when PL meets rolled around, he obviously changed things to peak for the meet.
There are some issues with this idea:
1. It's not sexy doing the "base" work and it's slow going.
2. You can't program this like barbell work so it requires that you have some patience and some creativity.
3. This cannot be taken as a license to JUST do the same base movements, over and over. So if want your dips/chins to go up, you obviously have to do dips/chins - but you should also be doing rows, pulldowns, push-ups, DB movements, etc.
4. This doesn't mean you do 100000 movements/day. It means when you do these movements, you try to get strong as hell and don't mail it in. HOWEVER, when training for a peak/1RM - those last few weeks are when you can mail it in a bit.
Understand that you can go awhile with just the main lifts or main lifts/little assistance. But at some point, it's going to be VERY hard to push past a certain level. The LONGER you can hold this off, the better you will be. And the way you hold this off is by starting slow/progressing slow and working your base (floor) like a rabid dog. EVERYONE wants to add weight to the bar as quickly as possible. This is fine but what always happens is that you reach a level that you can't ever seem to get past because you don't have the muscle/base to get you past it.
I screwed this up in my own training when I was younger AND once again when I was much older/stronger. As I stated prior, building the base isn't complicated or overrun with a ton of movements/work. It's steady and consistent. This base building is one reason I really, really like body weight/west vest movements for most people. Because these exercises/movements are so weak for most people that the act of getting these simple things better can make a huge difference. For most average people, if you don't have a simple base of fitness (strength is part of it, too) you don't get to be confused when you hit a wall.