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

Well, certainly, if the speakers match the room poorly. (I am assuming, for purposes of your question that the “quality speakers” are not dynamically limited, are capable of undistorted low bass to 30 Hz and have a treble response to 20 kHz.) Every residential room has room gain in the Bass between 40 and 50 Hz. The trick is to have the room gain complement the speaker’s anechoic bass roll-off the achieve flat response in the room. To some extent, these problems can be ameliorated by placement (in or any from corners), and of course there’s always active equalization. There is no one universal solution that the speaker builder can design for, because rooms are different. Likewise, at the top end, a flat treble power response will sound unbelievably bright in all but the most heavily damped rooms (heavy drapes, thick carpets, lots of upholstered furniture). Again, because rooms vary in reflectivity, there’s no single perfect solution that the speaker designer can employ that will work everywhere.As with bass, there are possible adjustments to the room that can make the speaker “fit,” but that begs the question as to which is subordinate, the room as its decorated, or the speaker. If we listened to stero outside in an anechoic environment, then this would be simple. However, since we listen to speakers in rooms of varying characteristics (not just size and shape), a quality speaker in the wrong room can be a limiting factor in system performance.

You have received some very thoughtful answers through which I have learned some things here.   In my experience, outside of differences in speaker quality, amp/speaker compatibility issues, and sonic preferences of the listener, the bass response is the most difficult to get exactly right and (for a given speaker) is the parameter most influenced by the room.  Therefore, depending on the speaker and the room, I can envision conditions where a quality full-range speaker could indeed limit performance of a system.
I recently improved the sound of my system by switching from near full-range speakers to large stand-mounted speakers (two 9-inch woofers in each sealed box) along with two high-quality powered subwoofers.  This set-up provides a more consistent bass roll-off above 40 Hz (due to the sealed box), better overall integration of bass in the room (due to the superior control of the dual powered subs), improved bass definition, and overall lower frequency extension to below 20 Hz.  The ancillary benefit is slightly better clarity through the midrange.

One last point.

For some perception is reality.

An obvious after the fact result occurred following some of my previous steps up the audio finesse ladder as more costly items arrived replacing former old friends.

The overall sound quality. The sonic presentations. All seemed to remain the same tenor. Resolution gains were made. Better imaging developed. Bass was more robust and defined.

However, the voice of the outfit seemed to remain pegged pretty much at one point along the accuracy to euphony line a dot or two on its warmer side.

None of my latter audio arrangements sat squarely on neutrality. The previous earlier versions were busting down the doors of uber analytical and detailed, ushering a migration towards or away from crtical incisiveness.

What I’m saying is I feel a person’s listening preffs, genres notwithstanding, stay put once they’re matured or achieved.

You like your steak a certain way. Your coffee just so. Clothes and shoes need a certain fit in form and fashion. Music you are paying for to hear repeatedly in your home appears no different. Speakers need a certain aire about them esthetically and sonically to be there in the first place.

It follows then, if a major speaker upgrade is perceived and transpires how is the significance of the exchange then quantified?

Consequently, there’s a real good argument for ‘we’, or ‘us’ being the true bottleneck.

Well, that and money. Maybe a wife’s acceptance factor too.

BTW… on the WAF aside, just include the cost of some very nice jewelry in your proposed speaker upgrade and your choices for speakers will increase dramatically. Or should.

Predominately though, its us or the lack of $$$ which limits a system in at least one or two very under appreciated contexts.

Butperhaps that’s just me.