Yep. Each new big event/competition makes existing ones less popular. Back in the day when this "Events and Competitions" section first came to be, it was booming because there wasn't much else happening. Now with "Card Ideas" section, War, etc., people have less time to participate in these competitions.
Numerous people have been asking for more different kinds of competitions and events but because of the reasons above, I don't think we should go nuts here. If we just keep adding new stuff every week, at some point players just run out of time and all events suffer because of inactivity.
New default time for competitions is 14 days. Gives people a bit more time.
Yeah, that was a bit off-topic, sorry.