"In practice, it seems people who know how to maintain wealth would never keep a large sum in cash around, but quickly turn it into net income generating assets"

Warren Buffet famously holds large sums of cash or cash equivalents from time to time. Dumping your cash into overpriced assets just to keep your cash balance low is no smarter than hording cash.

http://www.forbes.com/sites/sharding/2013/09/20/has-warren-b...