That is a loaded question , for example a $4k speaker n average only $1k goes into this including packaging ,this too applies to electronics ,the rest R&D overhead and markup, this why you truly spend what you can afford to spend , That being said
after say $50k on a Loudspeaker the differences to $75k maynot be as substantial say from a $5kto $15kLoudspeakers , the parts quality gets substantially better .
for $5k that’s a good starting point , you willnot have even average quality Xover parts ,and drivers ,cabinet meaning both speakers are roughly $525 each including the packaging ,sad but true .having owned. A Audiostore MFG need to make this ,with Audiocables the profit margins on average far bigger . That is why lower priced items can be modded much easier .for Digital for example $5k is bare minimum for a good quality digital front end for example the exception $7k T+A 200 dac is a bargain vs even dacs at 2x the cost. digital cables say 2 Ethernet cables ,and usb$3k a good Ethernet hub Sonore ,or uptone audio $550+ $750 for A very good linear powersupply such as the excellent Linear TubeAudio . + Audiocables another $2500+ minimum everything adds up ,iam just speaking of a $50 k Audio system To many older audiophiles $50k is not even close to a top quality sounding Audiophile System.I have been over many professionals homes near the Boston area with systems exceeding $150k , when i owned a store I spent $50k fora$100k system .I am now approaching 65 and just rebuilding and-just over $50k is my cutoff to get exceptional sound quality after That you can do much better sounding still but ,at a very high cost , $$ diminishing returns . My point is don’t be frugal if you can afford more within reason.