After you achieve a certain fidelity level of gear, there is no endless upgrade, but only the need to try something different. One can get bored with the same sound from the same gear all year long. Manufacturers don’t get brighter and brighter by the day and can keep offering you better sound... they rinse/repeat/rehash the same thing in different packages (market it differently) after a certain point.
I have 2 multichannel rigs and 3 stereo rigs in 2 rooms to mix it up. They tend to sound very different (different forms of entertainment) and i won’t be selling any of it.