As a diehard fan, I never noticed that marquee events last only a single day or two -as I've always played though them mere hours after their release - but this must be the case as I missed the entire Qi'ra event this weekend while I was in the mountains, well away from WiFi and out of 4G reception.
I had always thought the Marquee lasted as long as the packs were in the shop. "Having a hard time deciding if you want to drop $400 for this character? Try them out!"
My frustration is that I actually enjoy being coached through the kits of these new characters, not to mention the free shards. As a "whale," I've never felt less inclined to purchase a chacter than right now, despite the fact I'm only missing out on 55 shards.
These events should last as long as the shards are purchasable. Period.