Actually if an Indian company gets sanctioned in the same way Huawei is getting sanctioned, having all the manufacturing capability is not going to do a damn thing. Huawei is not short of manufacturing muscle. What is denied to them is something totally different. It is among other things.
1. Market access.
2. OS / App marketplace access.
3. Software and standards to synthesize cores : Think Mentor graphics softwares like CADENCE.
4. IP Cores from fabless fellows like Qualcomm
Hence the need to have end-to-end technologies. Both software and hardware.
None of these things require a manufacturing base.
That's the next step of technology denial.
For example, TSMC is a Taiwanese company. Great. But what happens if, within the next 5-10 years, China takes over Taiwan? Even China will be able to sanction India, not just the US. One can sanction supplies, the other can sanction IP. US can even sanction supplies if they want to, they have both.
I don't think you have still realised the importance of GoI designating fab plants as a strategic sector. It means it has to be run in the country even if run at a loss. Right now import substitution is the most import thrust area for the next 15 years when it comes to manufacturing.
Matters relating to promotion and manufacturing of Semiconductor Devices in the country.