I had that experience with Yahoo. I sent a single email to my brother whom has an account on Yahoo with SPF, DKIM, and not in any blackhole files. I received their 421 response "All messages from x.x.x.x will be permanently deferred; Retrying will NOT succeed." and my only recourse was to fill in a "bulk email prioritization form" I was not sending bulk email and was thus denied for that program (nobody read my explanation that I am NOT a bulk mailer). It took over a month of contacting various channels to get them to take my mail.
I understand spam is a problem but email is perhaps the last communication identity you can own, and have interoperate with others. I have had my own domain and own email for 16 years now, and I am not going to give that up. Free email services come and go, but I own my identity.
I think the problem with DIY/small business email is that it is surprisingly difficult to set up a proper mail server. Sendmail book is about 4 inches thick, and my current setup is using 3 projects to achieve a simple mail server with SSL auth/IMAP. (Dovecot, postfix, SASL). I am a software dev, but even very good sysadmins I know do not want to have anything to do with email anymore and will often farm it out to Google.