Affordable vs. ultra expensive speakers - what's the difference?

Whats affordable for you may be cheapy stuff for someone who earns allot more. whats affordable for that guy maybe too expensive for you.

Regards, I would still say focus on a Good Room first as this will make allot of the diffrence.

Affordable (anything) vs Ultra expensive (anything)

Whats the difference?

Competing at the Olympics vs Winning a Gold Medal.

Whats the difference?

Acceptable vs Excellence 

Whats the difference?

The difference is everything, and the only thing.

I understand the diminishing return of higher cost speakers.  In term of driver technology, both speakers seem to be in equal.  The monitor metal dome technology does not seem to be inferior vs. the yg speakers.  They are not of garden variety but the product of extensive computer simulation.  In term of cabinet, the YG cabinet is made of aluminum so it has some advantage.  In term of xover component, the YG probably has better, higher  price components.

Overall, I think the only thing that justifies the price of the YG is the aluminum cabinetry.  But that alone does not seem to justify the 50K asking price though.

Having owned $2,500, $5K, $12K, and $34K speakers I assure you performance jumps are the primary reason to purchase ever increasingly expensive speakers. While cabinetry costs increase they most get priced for perform. The diminishing returns argument doesn’t really work until you get way up in expense because audio systems are like instruments, they get more sensitive as they get better and as such get more compelling to listen to. 

There are certainly differences, in every aspect of sound quality. 

But if one is expecting the differences to have some sort of 1:1 (for every $ more I spend, I will get exactly that much more improvement) correlation, that will not happen. 

The higher up the scale one gets, the less the improvements will get. A $50K speaker, will not sound twice as good as a $25K speaker. But, it will probably sound quite  bit better than the $25K speaker, than a $100K speaker will over a $50K speaker.

That being said, the difference the YG Hailey will have over the Monitor Audio, will be appreciable. I have heard the YG's plenty of times, and I have heard Monitor Audio before (not the ones in the link), so, I am speaking from pretty good experience. But, pretty much all aspects of preproduction will be better with the YG.