Big speakers, are they really the best way to get great sound?

There is no issues or relationship between room size and speaker size. 

When you fix and adjust those issues:

Generally, the speakers were right on edge of overloading the room, depending on music, the dreaded bass boom could be heard.

Fix and adjust is just like Erik saying:

get measurements and professional room treatments, and consider EQ when and where possible.

But it is correct that small speakers don't go that low and not that loud at those low frequencies and therfore someone can easily get away with not setting up a "good" listening space by skipping those two things!

Bigger speakers usually has bigger drivers that are able to pressurizeing lower frequencies and louder at those frequencies. 

And standard consumers they get to the conclusion oh those big speakers "is overloading the room" or "the room is to small or vise versa". 

Yes, that might seam to be the "logical" conclusion when there is a rather big knowledge gap and the general listeners don't know and don't have the experience of what a treated room and what issues that are able to solve. And the same goes for modern PEQ (DSP). 

To be brutal honest there is the majority that JUST plop a speaker of any size into room of any size. Without doing any room treatment or PEQ whatsoever..

And then it is the "fault" of the speaker or the room! (think again) 🤔

So do you know how, where and what to do as sound treatment. And know how to measure, use a computer and upload PEQ to your DSP (fix also issues with "dedepending on music" with different presets,) . 

Then room or speaker SIZE is no issue or relationship in my opinion. 

It is just simple relationship in physics as bigger speaker need more adjustment when it is working in a range there smaller once don't and that is independent of room size. 

It is as simple as that. 🤫💖

(A tip for getting the "best" sound and better than the sound that OP listened to, cost no object. Is to learn and master those two aspects. Then you can get whatever sound quality that your hart desires.

The other road is if you don't learn and evolve you are stuck in buying of the shelf speakers all your life in hope of that maybe one day. You will get something that is super on some tracks and less good on other tracks just like the OP describe. In the long run it will pay off.) 

I've noticed recently that "Bookshelf" speakers seem to be getting larger and larger...trying to give us a sound that's closer to Towers.....hmmmm....

Until recently I’d never been able to treat a room to optimize the sound. When I was a younger man my solution was to take  my speakers outside away from all reflective surfaces, with a lounge chair centered just right... I lived out in the country so the birds were really the only noise distraction..   My “large speakers” sounded infinitely better outside versus my small 2 ways, even though the smaller ones were a “higher end brand” and big ones were not. No comparison. Inside my house, the small 2 ways sounded better and I could listen for hours  - but they did not sound as pleasing as the big boys sounded outside. Obviously many other factors could be considered in my little indoor/outdoor “experiment” .. but I think the people talking about room treatment etc. are on the right path here. All else being equal bigger is probably better…and YES to using dedicated subs to allow for low frequency tuning. 

My girlfriend says she really likes my big speakers. Completely satisfied.

She has amazing big speakers too.

We must learn basic acoustics...

The size of the speakers is secondary provide they are of good design ...They for sure must correspond to your goal and room dimension ... But this factor so important it is to begin with is secondary relatively to the basic acoustics knowledge necessary to well embed the speakers for your ears in this room ...

I own 4 inches active speakers in near listening i modified and i had clear 50 hertz...

I am in heaven ...