Well, did you have an email server for your family, friends, and your small business? And someday your friend or customer using it reported that there's no incoming mail from Google nor their email to Gmail addresses aren't delivered. You check the reason and see that for Google - "because they fight spam" - your IP address seems to have a reputation not good enough for accepting email from your server. No discussion, no reason revealed, no way to appeal, no human on the other side, and nothing can be done. Of course, you can outsource mail delivery to one of the big email operators - big enough that Google doesn't try to block them even if they allow for spamming.
This way the very idea of email as a common, freely available service is strangled step by step for years.