Ultimately, a company has to pay up, or liquidate what it has in order to pay its debts. If it can't do that, then those who hold equity get shafted. That's just a function of the capital structure.
A government uses debt to pay for stuff. If it defaults on its own debt, it hurts its ability to generate funds without printing currency. So if a government defaults, it not only incites domestic panic and foreign wariness of its markets, it also loses the ability to affordably borrow to pay for programs that can right the ship.
Even for companies where bonds are pricing in a substantial probability of default, it's a big deal if they fail to service their debts. Sprint can survive a 30% drop in its stock price. It probably can't survive defaulting on 30% of its debt.
A government uses debt to pay for stuff. If it defaults on its own debt, it hurts its ability to generate funds without printing currency. So if a government defaults, it not only incites domestic panic and foreign wariness of its markets, it also loses the ability to affordably borrow to pay for programs that can right the ship.
Even for companies where bonds are pricing in a substantial probability of default, it's a big deal if they fail to service their debts. Sprint can survive a 30% drop in its stock price. It probably can't survive defaulting on 30% of its debt.