I’m very careful with privacy and security so I was surprised I got an obvious phishing email from “American Express”. I reported the email and moved on only to get another one today. I checked haveibeenpwned and it came back clear. I have never gotten a phishing email before the other day. As for the senders, they all came from generic IT sounding email addresses. They obviously weren’t American Express.
Have you given your email address to any other people you know? If so they probably put it into their contacts. They then use apps like whatsapp, insta, snap, etc which request access to their contacts. These companies then sell that information to ad companies. Tadaaa.
Honestly, no. Not that I know anyone who I’d want to have my email. I see your point though.