Can a Quality Full Range Speaker be the Limiting Component in a system?

There are a few slippery, impossible to absolutely define, phrases or assumptions in your inquiry, such as;
"... quality full range speaker"
"... limiting component" 
"... bottleneck" 
"... speaker's performance has been fully optimized" 

Now, if you get those parameters sorted out you can answer your question.  :) 

@douglas_schroeder   Doug, appreciate your post. Points well taken. 

How would you re-state the question or problem?

My only experience with a "full range" single driver speaker was the Hornshoppe Horns. Within it's operating range it was really nice. 
Sometimes wonderful.
That's the problem. 

All the best,
Nonoise

In my experience the answer is "unlikely". Assuming the speaker is not fatally flawed in some way my experience is that upgrading the source makes the speaker sound better. I currently have a mid six figures system in which the speaker is less than 10% of the system cost yet every time I upgrade a piece of the system the speaker sounds better. No doubt a more expensive speaker could sound better but it would need re-optimizing the entire system around it. System synergy is the key and I would suspect that unless and until the room changes (bigger for example) a well matched speaker still has a lot more to give

My experience is the same. Unless there is a big room change or you want a very different sound or start listening to the kind of music that your speakers are not up to, orchestra music as an example, good speakers don’t need to be replaced.