Every nation has different roles for different types of assets and platforms according to their military planning and doctrine. They can buy some and make some. The key is what they are capable of producing in indigenous fashion, without depending on external sources. Which is not what India can do.
Do you know that the SU30 the Chinese "bought" was also produced in China itself as J15 and J16 ?? All the systems in these J15 and J16 are made in China itself (WS 10B engines, avionics like AESA radar). China's deployed J16s (more modern than India's SU 30 MKI) will exceed 350 plus units now. How many SU-30 MKIs does India have ?? About 259 ?
@Jiangnan I don't know if I am entirely truthful above.