According to a friend at a large ISP who engineers their anti-SPAM, 93% of all email they receive is SPAM and dropped before routing to your junk folder. So for each 1 you receive, several dozen were sent to the bit bucket.

I work for a company that sales anti-spam and this is absolutely true. It is an unending battle between spammers and the people building the filters. We are also constantly getting RBL'ed by groups including Google and Symantec who know who we are as we have had business agreements with them in the past.

Anecdotal but I never receive spam in Gmail, neither in my GSuite inbox nor Gmail.

Also anecdotal, but I get maybe 1 spam/month in my GMail inbox and the same amount in my fastmail inbox.

But how many important real mails have you lost because you didn't check the spam folder?