DMARC reports show attackers exploit weak authentication, exposed emails, and domain trust signals, regardless of organization size.

Just realized I never raised a question about how bad actors decide which domain names to spoof.
I review DMARC reports quite often, and sometimes I see companies with 300-400 employees having no spoofing attempts, even with p=none and no reporting implemented.
At the same time, I see smaller companies with teams of just 1-5 people experiencing 100+ spoofed emails being distributed every day.
The first thing that comes to mind is that they might register on various websites / leave their emails on shady blogs, leading to email leaks.
But is there any correct answer? Anyone?