As rightfully mentioned here, Most of the Dubbed movies are Commercial entertainers (Masala types).
Channels which Air such movies are having channels in almost all languages, hence for them instead of purchasing a new Hindi movie, dubbing a relatively old Telugu, Tamil or Kannada movie is cheaper.
Example : Star Group have Channels in Bengali, Marathi, Telugu, Malayalam, Kannada.
So they basically interchange these movies, come up with different combinations like Hindi movie dubbed in Tamil, Tamil in Hindi, Telugu to Tamil, Kannada to Tamil, etc etc., Basically from one movie you can 4 to 5 movies, which can be shown in 4 to 5 different states, Comfortable aint it ?
Not only Movies, this trend is seen in serials too . Star Vijay is a Tamil channel is the first c to Air dubbed Hindi serials, to my surprise its watched in equal number as the Original Tamil series. So channels are making double money from one serial ( Excluding the dubbing technician charges ).