Mortuary services. More seriously, I think there are a couple of possible meanings to the '-ary' progression: if more abstract, making use of the lower levels,

Mortuary services. More seriously, I think there are a couple of possible meanings to the '-ary' progression: if more abstract, making use of the lower levels, the quintary must be finance. If the progression is 'less directly crucial to life', then it probably is the whole service sector. Entertainment would be pretty far out there. A 'mixed feeling' aspect to this is, that free software is greatly helping this along.