Is Debt Necessary for Wealth?

Debt can ease the intertemporal budgetary constraint and be used to create leverage… and create wealth if profitability exceeds loan cost. Yet, 2008 and 2011 crisis have recalled excessive indebtment can undermine our economic system as a whole and impact many interconnected countries. Then, how to determine when debt becomes excessive?
For households, the question seems rather simpler, as the intertemporal constraint is finite. Yet, many poor households end up overindebted. How to regulate the system so that we avoid this situation?

For firms, dept is an inevitable tool to finance their growth. But what should we think of those who take advantage of low rates to buy their own shares to distribute dividends? This use of the leverage effect falsifies the debt initial object. And, at the end of the day, are the firms “richer” or is it the shareholders?

Lastly, are the current sovereign debt rates sustainable? Will the inevitable financial crackdown to come slow economic development down? High debt rates also shorten leeway of economic policies to counter cyclical chocs. And what can be done about the potential loss of sovereignty (for instance the increasing debt in African States following Chinese massive investments)? If rates finally rise, it may be an additional factor of instability.