is investment the main reason some countries produce low quality shows?

Investment, scale, but no.

Netflix has the best of Hollywood and international talent on tap, they can pull producers, directors and show runners and give them plenty of support.

Beyond that, India is a huge market, but still far smaller in terms of revenue compared to the US.

Finally, and I say this as someone who can, India is both revolutionary and hide bound when it comes to media, lot of innovation, but unlike in the west, that innovation doesn't always drag the entire industry along, much of Bollywood is going back to what worked, but with a slightly new twist (with definite exceptions). A huge segment of their audience is still old ummas and thathas who want to watch the same thing as when they were young.

Indian audiences were largely possible to satisfy with less innovation for decades, now their sheltered market is being overwhelmed by newer competitors.