Newspapers are predominantly printed lithographically with cold-set inks that set by penetration into the absorbent paper stock.  Printers who print daily newspapers may devote considerable press time to it, but those printers who print newspapers for smaller towns and cities that publish only weekly or bi-weekly may find considerable downtime.  The presses represent a costly investment, and it is desirable to have enough jobs to fill available time.  Consequently, printers may seek other jobs such as insert material, covers, and color advertisements.  Many of these print jobs, however, require heatset equipment to print on coated stock for printed materials with better gloss or better print definition.  The cold-set process is capable of printing only on uncoated (thus absorbent) stock. 
Modifying the press to print heatset inks would require significant additional equipment to be added, particularly ovens and solvent reclaim or incineration equipment.  This would add a lot of expense and require a lot of additional space.  Further, the heatset inks would need to be compatible with the rollers and blankets of the press, which are rubber materials.