That is the complete opposite here. They are very popular and most malls or hang out places have a store each. I don't drink coffee much so I don't care about their coffee as well.
For the stickers, I did a bit of research, and they actually have a separate website for the Christmas tumblers and planner for sticker redemption. I don't know when this started but here is the site if you want to check how it works.
https://starbuckstraditions.ph/#collection
Starbucks have to use stickers to entice customers there? The coffee should be doing that job.
The coffee/ambiance/hang out place already pull a lot of customers to them, but this sticker+planner combo makes them rake in the cash. People like the challenge, and have a reason to hang out there. When they do get the planner, it is a sense of accomplishment for them.
I think I have to disclose that I do not work for Starbucks, I am not sponsored by them, I do not endorse them, and I don't usually drink their coffee. haha
You're Mr. Starbucks! Although you don't work for them, I hope they see this and offer you...well, at least some stickers!