Depends on your provider. My GMail is fine, but my much older Hotmail is a spam cesspool. It's so bad I barely check it anymore the last couple of years, despite having been able to keep that email address since something like 1996. As I had "exposed" that to some email farms I probably got into some really bad spammers lists which Microsoft seems unable to stop.

Spam evolved. The filters catch most of the egregious kind, but our mailboxes are still flooded with the rest: marketing of legitimate companies, which you likely interacted with at some point, however briefly, and often mixed into transactional messages. This consists the majority of most people's inbox; I bet it's the case for you too.