why ?
Why the N.Y. accent is disfavoured
I have the impression that what's now called the New York accent used to be associated more with the uneducated classes (in the past, not as much now). I base this mostly on a source that's not very reliable, the movies of the 1920s and 30s. In those movies it's nearly always uneducated, lower class persons who have the New York accents. The upper classes try to sound sophisticated, and to do that sometimes adopt an accent that sounds slightly British. I'm sure part of this was from the actors themselves (a stage accent), but still I believe that the upper classes had less of what's now called a New York accent than the lower ones. (Even if not true, the movies would help create this impression in the rest of the country, and thereby cause the accent to be disfavored.)
Switching to real poeple, both Franklin Delano Roosevelt and his wife Eleanor were from New York, and I've often heard excerpts from their speeches. FDR didn't really sound British, but I don't recall his sounding much like New York either. Eleanor may have said a few things that sounded British (anyway I have the impression that she had a pretentious upper-class accent).
Also in many things New York (the Northeast) is seen by many Americans as being on one extreme and the South on the other. The Midwest falls somewhere in between, so there tends to be less antagonism towards that region than there is towards the Northeast and South. That may have caused people to have a more favorable view of its accent. Also I don't believe that educated Midwesterners were as likely to attempt to imitate a British accent. So they could speak with an authentically American accent and not have it be associated with ignorance.
Anyway when it came time to choose announcers for the national radio networks many from the Midwest were chosen, and in time professional announcers from other regions tended to suppress their regional accents and try to sound like they were from the Midwest. I believe there's much less of that nowadays, and the New York accent is more accepted than before. Compared with Roosevelt, Rudy Giuliani has an obvious New York accent. John F. Kennedy, with his New England accent, did much to help make extreme accents acceptable. At first his accent sounded downright bizarre to most people, but with time they got used to him. For national announcers, though, I'd say that the Midwestern accent is still preferred (or the General American Accent that resembles it).
[As I said, those are just my impressions, and I could be totally wrong about much of what I've said -- in my entire life I've just spent two hours in New York.]
Switching to real poeple, both Franklin Delano Roosevelt and his wife Eleanor were from New York, and I've often heard excerpts from their speeches. FDR didn't really sound British, but I don't recall his sounding much like New York either. Eleanor may have said a few things that sounded British (anyway I have the impression that she had a pretentious upper-class accent).
Also in many things New York (the Northeast) is seen by many Americans as being on one extreme and the South on the other. The Midwest falls somewhere in between, so there tends to be less antagonism towards that region than there is towards the Northeast and South. That may have caused people to have a more favorable view of its accent. Also I don't believe that educated Midwesterners were as likely to attempt to imitate a British accent. So they could speak with an authentically American accent and not have it be associated with ignorance.
Anyway when it came time to choose announcers for the national radio networks many from the Midwest were chosen, and in time professional announcers from other regions tended to suppress their regional accents and try to sound like they were from the Midwest. I believe there's much less of that nowadays, and the New York accent is more accepted than before. Compared with Roosevelt, Rudy Giuliani has an obvious New York accent. John F. Kennedy, with his New England accent, did much to help make extreme accents acceptable. At first his accent sounded downright bizarre to most people, but with time they got used to him. For national announcers, though, I'd say that the Midwestern accent is still preferred (or the General American Accent that resembles it).
[As I said, those are just my impressions, and I could be totally wrong about much of what I've said -- in my entire life I've just spent two hours in New York.]