A government running like a literal business Hopefully this doesn't get partisan, but I wanted to see where a thought experiment would go where a government stopped collecting taxes and instead fund itself by running businesses (selling products and services) alongside other private businesses out in the free market.
This is an extremely implausible scenario.  The conditions for it to work would be extremely demanding:


The government would need to run businesses in which it has the
potential for a sustainable competitive advantage, giving it the
opportunity of earning profits on an ongoing basis. That might be
based on a natural resource endowment (cf Saudi Arabia and oil) or
on a technology which others are, for whatever reason, unable to
copy. For most countries, such opportunities are limited.
The government would need to run the businesses efficiently, so as
    to realise those profits. This would be challenging due to:
    a) political necessities conflicting with efficiency; b)
    rent-seeking behaviour by managers and workers in the businesses.
The profits realised would need to be sufficient to fund the
        government's expenditure.  For a typical developed country with high
        government expenditure on education, health, welfare, defence, etc.,
        this would require improbably large profits.  To give an idea of scale, UK government spending in 2015/16 was £772 billion. By contrast, the world all-time largest corporate earnings (Vodafone in 2014) were less than 10% of that at £59 billion.