Joel is wrong. The 2001-2003 timeframe was very hard to find a job, even if you were a really good engineer.
There is a good reason Open Source development exploded during those years, as there were a lot of unemployed or 'underemployed' good engineers that had time to do some open source work while looking for a job.
By 2005 (when that article was written), the market had already recovered, and what he said is true (good engineers had already found a job), but that doesn't negate the fact that 2001-2002 was bad even for good engineers.