Has anyone made the jump to $uper High end and were disappointed?

I've never heard Ayon sound good but have heard D'Agostino sound phenomenal. The lesson here is that the sound is in the ear of the beholder. What is most important is how it sounds to YOU.

Spending more $$$ is no guarante for better sound. If you make smart choices along your personal audi journey you will be able to enjoy what you love even more. A higher resolving system can be more rewarding BUT it can also make things worse when you suddenly hear a weak link that was burried before. Working on each weak link can be very rewarding when you manage to achieve improvements. It is like an endless very personal puzzle. And I agree with Robert Harley that the better (not necessarily more expensive) the system gets the larger the reward from small improvements. The oposite of diminishing returns is what happens, when the resolution of your system allows you to hear a significant difference just by changing a minor component. Just throwing big $$$ at it does not at all guarantee satisfaction!

Throwing - no, but super sound is expensive even if you buy used. Let's not fool ourselves.

Speaking of super high-end, $4000 only buy used/demo cable or used cartridge or rack, though some advocate that $500 vintage cartridges can be at least just as good. 
I will never be operating at this level, I think just high end will be satisfactory. And I won't need a lot of money for that, $50k or so for everything, I guess. But of course if I want custom headblock for Studer deck and outboard custom tube playback head amp, and something like Herzan active isolation platform, that will be extra.

Super sound? What is that? However, high end home audio is one hobby where "fool yourself" (not the Little Feat song) is a defining characteristic.