Is the use of the positive "anymore" considered correct?
Solution 1:
Here is what Bryan Garner, Garner's Modern American Usage, second edition (2003) says about anymore used in the sense of "nowadays":
anymore. A. Meaning "now." In the sense "now," "nowadays," or "still," the word anymore fits in three contexts: (1) negative declaratives {you don't bring me flowers anymore}, (2) yes–no questions {Do you go there anymore?}, and (3) hypothetical clauses introduced by whether or if {I wonder whether they go there anymore}. In sense 1, the meaning is "now" or "nowadays"; in senses 2 and 3, the meaning is "still." When anymore is used in some other type of positive statement (not in sense 2 or 3), it is dialectal—e.g., "The price of housing is outrageous anymore {read these days or nowadays}." In a [1986] linguistic study of Missourians, informants considered this dialectal usage "well established though controversial." [Citation omitted.] That mans that the informants were all familiar with it, but many didn't like it. The findings would probably hold throughout most of the United States.
Garner notes that anymore is standard in U.S. English when it appears in negative constructions ("Don't do X anymore"), in questions ("are they X anymore?"), and in hypotheticals ("whether we X anymore"). But in positive declarative statements such as "People are rude anymore," Garner holds (accurately, in my opinion) that the usage is not standard across U.S. English, but dialectal.
The form of expression has been around for a long time, as is evident from these examples reported in Harold Wentworth, American Dialect Dictionary (1944):
1903 s.e.Penn[sylvania] Lancaster Co[unty] There's just only this one any more. Martin 'Ellie's Furnishing.' ... 1929 Iowa 'Any more I don't like the boughten [ice cream].' Characteristic. K. Buxbaum. 1930s w.cent.W[est] V[irginia] Charleston We still use that custom anymore. 1931 s.w.Penn[sylvania] It's quite warm anymore..It's pretty poor anymore..Anymore I never see him. ... 1932 cent.Ill[inois] Dewitt Co[unty] 'We used to go to Weldon Springs for picnics, but any more we go to Salt Creek.'Common. C. W. Carter, Jr. ...
Although Wentworth indicates that Northern Appalachia (West Virginia, Pennsylvania, Maryland, and Kentucky) is the primary locus of such usage, he also finds instances from New York, Ohio, South Carolina, Kansas, southern Ontario, Michigan, Montana, and (as noted above) Iowa and Illinois. The examples of dialectal any more in American Dialect Dictionary, despite being set in small type, come close to filling two complete print pages. Still, notwithstanding such wide distribution, the expression remains dialectal—and Wentworth reports no instances from New England, the Pacific states, much of the interior West, the Southwest, and much of the South.
So the answer to your question "is the positive use of anymore considered correct spoken/standard written English?" seems to be that it may be considered so by English speakers for whom the dialectal use is natural, but not by others. And as Garner remarks, even in areas (such as Missouri) where the usage is currently familiar to many people, "many didn't like it."