There are dozens of professors at the universities who does not produce single scientific paper in a year. To be very soft, it looks to me not good. Some has an arguments that they are making very important research and therefore it needs time, but years passes and nothing happens. I think this is not good. I divide scientific papers in 3 categories: 1. Weak paper; 2. Regular; and 3. Good.
All three categories can be published in PR and IF journals. Weak papers can be published more frequently, however they can give very important information, which will be used by other colleagues in the future. regular papers are more rear and Good papers can be very rear.
Therefore I would like to summarize that self-exculpations from the professors side that they are making important experiments and they need years to publish, does not look correct to me. At least they can publish weak (but with important notes) papers in a year. Otherwise anybody can claim that they are scientist who has a diploma.