It may be true that there have been fewer events throughout the day lately, but event frequency is not something that is regulated. Staff don't have a quota, nor are they limited to a specific number of events for a given amount of time. Personally, I try to host one event every day, but it all comes down to how much free time a staff member has and how well the server is under-control.
Classic has had a significant playercount boost lately, and that means a lot more reports and general shenanigans. If there aren't very many staff members online, doing an event can increase the amount of player-related issues on the server; one event can put the staff member out of commission for a decent amount of time, having to sift through several hundred PMs, answering questions and looking for anything important.
In summary, events have been more difficult to host recently unless several GPs are online. Yesterday we had quite a few. Maybe some of you saw the "Mega Event"?