Well then they for sure can't use gmail. If you still do use gmail, please consider moving to something else. And until you actually do, make sure to keep a close eye on the spam folder because you've most probably lost important mails.

Gmail is actually better than the competitors at filtering spam

I couldn't disagree more. I have several email accounts and the gmail one by FAR lets through the most spam, a lot more than my Fastmail emails which despite being more published have far less spam than Google.

But do you know for a fact that it lets through a larger proportion of the spam sent to it, or are you just noticing that it gets a larger total volume of spam than the others? Because if it's the latter, that could be an effect of more spam being sent to your gmail than to your other accounts.

That's hardly impressive and a small comfort when they are better than their competitors at filtering real and important mails as spam.