It has changed. Whether it is better or worse depends on your point of view and what you expect from a dealer. Newer dealers, like High Water Sound and In Living Stereo, sell niche products. Oswald Mill in Dumbo is fascinating (I'm still due to visit). Some of the old guard- Lyric, Park Ave, Harvey, Singer are gone or moribund. Rhapsody looks like it has fabulous showrooms. Harvey Rosenberg and Cello were interesting while they lasted. Stereo Exchange was once a clearing house for used high-end equipment, with stacks of ARC preamps and amps, Goldmund tables and tons of used speakers, cable and the like. With the advent of Audigon, that's history. Innovative moved from Brooklyn to Manhattan and I gather it is now OK if you don't have a Linn turntable.
For the 'greatest city on earth' I'm not sure the retail scene is any better than any other major metropolitan area. The old radio row is long gone, and finding venues to hear live music is not as easy as it once was with the closure of many famous clubs over the past 15 years or so. That said, there is a strong audio community here, and New Yorkers somehow manage.
Lee, you'd be surprised at the number of Manhattanites who are holding heavy iron too. I used to see a guy I know driving his Ferrari Daytona early in the morning from the city out to the country. He used to run the car outbound while everyone else was sitting in traffic on the inbound commute. He would roll back to the city later in the morning, when the traffic was relatively lighter.
Oh, and quite a few reviewers lived or still live in the metro area.