If we classify projects into four categories by important vs. unimportant, and interesting vs. unpleasant, we can assess what happens under open allocation.
Important and interesting projects are never hard to staff. Unimportant but interesting projects are for 20% time; they might succeed, and become important later, but they aren’t seen as critical until they’re proven to have real business value, so people are allowed to work on them but are strongly encouraged to also find and concentrate on work that’s important to the business.
Important but unpleasant projects are rewarded with bonuses, promotions, and the increased credibility accorded to those who do undesirable but critical work.
Michael has a strong understanding of the incentive undercurrents that exist in technical business environments. I highly recommend subscribing to his site.