I have a friend who has just spent £700 on a fuse. If he can't afford it nobody can, and if it keeps him happy etc.. But I can't hear, nor convince myself that I hear such differences.
Equally, I'm unconvinced that figures like £15k can be justified for a DAC. Basic DAC chips can be had for pennies, better ones for maybe £100 tops. Yes, I know that DACs are as much about component implementation as DAC chips etc cost, and of course R&D cost too, but £15k? Pull the other one.
I'd argue that in the right context speakers ranging from Tannoy Westminsters through Quad ELS 57s to Rogers JR 149 can all be 'unbeatable'. Same applies to numerous vintage/ veteran amps and so on.
I M E the major improvements in hi - fi are in the 'democratisation' brought about by huge SQ improvement at the budget end of hi fi, mostly brought about by digitisation, streaming etc.
People who ( Like me) would have had to be content with a Dansette ( or one of the many much less capable mass market offenders of the time) are now able to access much better SQ, and those of us fortunate enough to afford even the lesser offerings of the likes of Rega Linn NAIM, Michell, Denon, Rotel and many other Co.s are assured of decent SQ given decent component choice and set up.