There are many other, more pragmatic, reasons why an obsession with top talent can be damaging. They include:
You can't attract it. I know this is hard for you to accept, but your firm probably isn't the world's sexiest employer. Google can have its pick of the best software engineers on the planet; you, turning out boring banking software in Bristol, cannot.
Top talent exacts an unacceptable price. Think of all those star investment bankers who laughed at the stuffy old risk-management department while signing their mega-deals. Many of them continue to trouser huge bonuses based on short-term profits, despite having driven their employers to ruin.