What makes M&A So Attractive Compared to Organic Growth?

What makes M&A So Attractive Compared to Organic Growth?

I think one reason for the low success rate of M&A is that many times the merger arises from opportunity and not from genuine strategic planning. Sometimes board members meet loosely, see some similarities and the idea is borne.
Seldom you see an approach from a company vision and a mission statement as a base for a strategy that makes a merger a necessity.
With such a low success rate M&A becomes a high risk gamble.
Why is it then that boards so often perceive a high-risk and difficult to achieve M&A as attractive compared to organic growth?