Why do blackheads keep appearing even with proper care?

Even if I clear the sebum from my nose, it feels like it comes back after a few days.

I've tried oil cleansing and using nose strips, but it seems like they actually just cause irritation.

I'm wondering if blackheads are inherently difficult to get rid of completely.
There are some that are so firmly established that you can't get anything out even if you squeeze them hard.