A Counterpoints Research study has determined that TSMC has 28% of the market share in matured nodes (40nm and below), making it the world leader in the global semiconductor manufacturing market. UMC, SMIC and Samsung take second, third and fourth place with market shares of 13%, 11% and 10%, respectively.
https://www.notebookcheck.net/TSMC-has-the-largest-market-share-in-the-global-semiconductor-manufacturing-industry-Counterpoints-Research.518137.0.html
That is a key reason why China is eyeing TSMC and the TSMC is desperately trying to build fabs outside of China's reach. SMIC on mainland China is not competitive nor have the capacity to even serve its domestic needs.
I don't think SMIC is responsible for any smartphone SoC with widespread adoption, regardless of the node, so it's quite shocking to see that SMIC holds the title of No.3, but instead this really speaks to the volume of mature nodes compared against leading nodes.