Questions on Domain Verification Limitations

From the documentation, each account is limited to just 10 domains or addresses. Why is that limit in place? We have the need to go further than 10 domains, or be able to validate on just top-level domains.


As an example, these are 3 different sub-domains that we send email from:


abc.example.com

def.example.com

xyz.example.com


Do I have to verify each domain, or can I just verify the top-level domain (example.com) and its sub-domains will be also be verified? For email deliverability and localization purposes, we send from dozens of different domains. If using a top-level domain isn't possible, can the limit be increased?