Two points-
First- life is about the zeros. If you have enough zeros after your net worth, you can have more zeros after your audio system or other hobby. Therefore, the more interesting question is for those who have spent a higher % of net worth (for us older guys) or income (for you younger guys).
Two- we have a “luxury tax” in place at our household. If I spend $10k on a preamp, then we make a $10k donation to charity above and beyond our normal giving. This makes me consider each audio (luxury) purchase more carefully and has kept my system below the $50k threshold. It also keeps me driving a Toyota and not a Ferrari, which I could probably afford.