Why are there out-of-date tower frequencies on the VFR sectional chart, without a NOTAM?
It's not a printing error. FAA sectional charts are updated only once every six months. In order to to reduce the number of NOTAMs due to sectional changes (which can number in the hundreds between cycles), the FAA provides a section in the Airport Facility Directory (AFD), titled "Aeronautical Chart Bulletin" that identifies changes that have occurred since a chart's publication. Pilots should check this section on each AFD update for changes on their intended route of flight. Once the change is posted in the AFD, the respective NOTAM is taken down.

Here is an image of the applicable AFD page for Salinas, as of the date of this answer: