The main thrust of the argument is that "resources" implies some kind of average, that developers are interchangeable cogs in the wheel. But Peopleware taught us that there can be an order of magnitude difference between the best and average developers, so your scheduling and estimates are based not on some abstract "resource" but on the talent of the person involved. Talent matters. You have to build a winning team with talent, not by scheduling "resources" who you think are interchangeable. Those people are inherently NOT interchangeable due to varying levels of talent.