It takes a long time to build up IP reputation if you run your own infrastructure. Even today after a year+ on the same IP, DKIM/SPF/DMARC, senderscore of 100 and transactional email only, Yahoo still randomly blacklists us for weeks at a time. Good luck getting in touch with a human to figure out why when you aren't Gmail or another big player in the industry.
Aside from Yahoo though, we generally haven't experienced any blacklisting or deliverability issues. It does require time to setup properly and maintain however, you can't just set it up and forget about it.
That's exactly part of the problem. If email went back to decentralization properly, the whole idea of ip reputation could go away, which is genuinely wrong and against email in the first place.
Aside from Yahoo though, we generally haven't experienced any blacklisting or deliverability issues. It does require time to setup properly and maintain however, you can't just set it up and forget about it.