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

Will it sound $48,000 better?  No

Will it sound better than a $2,000 speaker? Yes

For the wealthy people, $50k means nothing. For the average joe, there are many other ways to spend that money for good usage. 

Sound systems need to have synergy with their components. A great sounding system could cost less than 3k in the used market.

some people buy $50k speakers an its still not end game!  just use your ears to judge, difference between $5k speaker and $20k is not that much of a difference.  the difference in cost will be the name and material used to make it.  If I am about to drop $30k on a pair of speakers, I'll take the B&W 801 D4.  They will sound and look great to my ears and eyes.