40 year index return from Indian stock market have been around 15 percent without dividend reinvestment.

The long term inflation rate has been 7 to 8 percent and bonds have returned par with inflation rates

It is in India.

I apologize if this is a stupid question but why wouldn't everyone be investing in India with these returns being standard? In the US we would assume a conservative rate of 7%

The 12% returns are not adjusted for inflation or depreciation. Historically, India had a much higher rate of inflation than the US. And the rupee has continuously lost value against the dollar.

US 10 year treasury yields are ~4% while Indian treasury yields are ~7%.

When adjusted for usd returns might not be that great. Indian currency have been depreciating a lot against usd.

On the other hand my own portfolio has a mutual fund that invest in US stocks for more diversification.