Being in the software industry working in NYC (but not anymore), I can tell you that there are many COMPETENT people who have been laid off because of many other reasons between late 2007 and 2009.
Some of them:
1) Financial firms want to move data centers to less expensive states and tell employees that they need to be prepared to move or else... ( and many don’t want to uproot themselves, so they take a package instead ). Nothing to do with their performance.
2) Financial firms embarked on an ill-advised project and find out that the market and general economic conditions have changed and there is no need for the project any longer. Continuing will only cause more money to be poured down the drain . result : Mass layoffs ( the good get thrown out with the bad and the ugly ).
Just two I have observed off the top of my head. Age discrimination is also rampant but I’d rather not get into it because the counter-argument would be -— you could be the victim of the Peter Principle.
And yes, there is also the separating of the wheat and the chaff, but we can’t ignore all the above that I mentioned.
All of what you say is true, but it’s anecdotal, and you are simply not going to understand the law of large numbers if you stay buried in anecdotal evidence. There are also different dynamics for different industries, and perhaps in the software industry, one where working in mom’s basement might lead to billionaire status, the “rule of thumb” is not quite as pure as it is in most other industries.
The fact remains, this survey is totally in sync with what we all know about human nature, and to try and believe otherwise because we are, or are related to, or know, some of the exceptions is simply a dead end realm.