3 elements help: No kids, don't over spend on other things, and bargain-hunt for used gear. Key concept: priorities.
A childless household is more likely to have the money, space, and time to dabble in music/audio pursuits than one with children. How many AudiogoN ads have text that says something like, " Selling gear because we are expecting a (another) child"?
I find it odd that audio "civilians" seem to take an incredulous delight in scoffing at the high prices of specialty audio gear; yet, they think it perfectly normal to buy new, gas-guzzling trucks or SUV's every three years; or own boats; or regularly take resort vacations. Buying that SUV, boat, or blowing money in Las Vegas is completely their prerogative. So, why does it bewilder the audio uninitiated that some audio nerds forgo trucks, boats, or Las Vegas (except CES, of course) so they can afford $25,000 (or what-ever) audio systems?
Lastly, as so many on this thread have pointed out, exploiting the used market lets the experienced audio geek assemble a satisfying music system for about half that system's retail price. Smart choices and good setup (vibration control, synergetic cabling, wise speaker placement, etc.) can go a long way. Often, well-assembled less costly systems sound better than do poorly assembled expensive ones.
A well-chosen music system can deliver a mind-calming, soul-stirring transformation in its listener on demand in her own home. I can think of far worse uses of funds.
(Disclaimer: I bear no hostility to children or loving parents who choose to replicate themselves in this World. I include myself when I affectionately use the phrases 'audio nerd' and 'audio geek.' No malice, humiliation, or denigration is intended to anyone who may have been called nerd or geek by others in the past. While I personally do not choose to own a truck or SUV, I do not hold it against anyone else who feels the need to do so. We live in a wonderful World in which even cities like Las Vegas have a place. I apologize to anyone who may have inferred harm from my comments.)