system
Given the following post, respond as if you're commenting on Reddit:
human
Why doesn’t the govt borrow money at the treasury bond rate and invest in an index fund with a higher average return?

The interest on a yearly treasury bond is something like 7% while the S&P500 has an average return of 10.7% over the last 30 years. Shouldn’t the federal government make use of this roughly 4% difference?

This is probably a dumb question but I appreciate any responses!
gpt
There are a few reasons for this. First, the government owning equity is very taboo, and represents a line that many argue should not be crossed. If there was a guarantee that the government would purchase equities, even in the form of an ETF, there would be a price floor created and moral hazard would be introduced. Therein, a company could act haphazardly as it would be assured that as long as it stays in the S&P500, their stock price would remain inflated. 

Second, the government has no need for this. The purpose of a government is not to create profit.