I believe both South Indian films and Bollywood film both look Indian and have feel of a desi touch.
Bollywood has modern touch because Bollywood film industry is headquartered in Mumbai , the most developed city in Indian subcontinent and has a Audience size of atleast 1 billion or 1000 million or 100 crores.
This means high quality visuals, large number of production houses and producers and everything is big.
South Indian film industry is not just one film industry it is actually 5 or 6. The market is very low compared to mighty Bollywood. It's approximately 252 million audience size.
Kannada language film industry or Sandalwood headquartered in Mandya, Karnataka. It's popularity is restricted to Karnataka only.
Mandya is primary hub of Kannada film industry.Mandya is considered a premier, high-octane, and loyal stronghold for the Kannada film industry (Sandalwood), often acting as a crucial barometer for a film's success due to its dedicated fan base. It is a major region for promotion, frequently hosting top stars.
Tamil language film industry or Kollywood is headquartered in Chennai and Kumbakonam. Tamil Nadu is the primary hub of Kollywood.
Telugu language film industry or Tollywood is headquartered in Hyderabad. Andhra Pradesh and Telangana are the primary hub of Tollywood. It's the largest film industry after Bollywood and the Largest Film industry in South India.
Malayalam language film industry or Kollywood is headquartered in Thiruvananthapuram. Kerala is the primary hub of Kollywood.
Tulu language film industry or Coastalwood is headquartered in Mangalore, Tulu Nadu state.