Just to pile on here, the cost of really good drivers has dropped quite a bit. I've owned speakers using most of the top line Scan Speak drivers, and the latest Dayton RS28F silk tweeter is just as good in most respects, and better than them in others. Scan's are $200, the Dayton is $70. Most importantly, beyond specs, it actually sounds as good as the Scans.
Now, for mids, it's a tougher field, the Scans and the top line SEAS drivers are still not equaled by less expensive designs. On the other hand, the cost and performance of very good woofers and subwoofers has definitely gotten better.
I'm also pleased to see that tube technology is getting better as well. The use of Constant Current Sources is a real improvement to traditional tube designs, and the cost is crazy low (about $30 in parts).
Mics have improved dramatically as well, and thanks to manufacturers like Earthworks, has brought very high performance/precision into the affordable realm. With the advent of really excellent (free) measurement software like HOLM Impulse, you can really get an idea of how your speakers perform.
Throw in an international used equipment website (audiogon), and it's very, very easy to put together a great system for quite a bit less than in the past.
What this means is that you can really, really put together a great sounding system