In a complex sentence, time relations bind the main clause to the subordinate. AS is a time subordinator.
If the time relation is the same we use, simple present is in both clauses:
We put the subordinate clause in present perfect to show a previous action before the main action:
- The weather is nice as it has rained.
Equally important is to note that when the main clause is in present, subordinate clause is put in present perfect to show an action that extends from past to present. However if the main clause is in present perfect, it is better to use present perfect in the subordinate clause to show another action related in time to the main action, as if simultaneous:
- Although the students have complained to the principal, he has not initiated any action against the culprits.
On the same principle the tenses in this Wikipedia article is based. The debate has started early and it is still continuing. The face-down effect has started already for a reason, so on and so forth, and is not over as yet. But none can foresee what lies in store for the media industry and if it would at all recover. Had we used simple present in the subordinate clause, it would seal the future of the newspapers once for all and suggest a kind of universality to all that is happening at present. After all it's not like such habitual or normal action as birds sing, flowers bloom or rivers flow.