It depends... The fb page I run has been liked by close to 17k people & you should see their mad excitement for Hindi Dubbed Telugu & Tamil films. Telugu craze is the highest followed by Tamil. Not much for Kannada & Malayalam. The amount of abuses I've to bear.
The dubbed films don't collect big, but the market it enjoys is basically on television. As far as theatricals go, it basically restricted to Gujarat, CP/CI.. But now South films directly release across the country without getting dubbed. OK Kanmani ran for housefull shows in Delhi.
And regarding inferior, apart from the big budget involved, most of south Indians consider Bollywood to be inferior to us.