Not using them in enough frequency or large enough quantities...I'd love to see a group orchestrate 20-100 scrolls launched within 1-2 day time period. *cackles*
There have been some minor usages of 5 or so scrolls at a time, but the continent-wide effect of that is only minor with that few number and infrequency of scroll usage.
There's around 600 summon scrolls on BT now. There will be some scroll improvements later (soonish), to help 'encourage' their usage.