The reason is fairly simple. As a small business, I need my email to work. When I do it myself or outsource it to a small company, it works most of the time ... but not always. I can't afford that.
Also it simply makes no sense spending time setting up, configuring and maintaining email servers as a business owner when there are more important things to put your time in.
This is unbelievably not true. Installing dovecot or similar is super easy. There are many options.
Unfortunately, setting things up to the point where your email isn't instantly tagged as SPAM by Google's, Yahoo's, and Microsoft's servers which handle the bulk of the email you want delivered ... is a monumental feat of engineering.
Frequently, they just mark it as SPAM when it doesn't come from one of the big boy's servers. What's the point of sending an email if the recipient will never have a chance to read it?
Are you sure? I've been sending email from my workstations for years and never had an issue. Maybe if I'd let spammers relay through them for a day or two I'd get blocked. Even that would just be temporary. Let's see some proof that you need a big boy's server to successfully send email. The only real problem I can think of is that a lot of ISPs block 25 out.
While I agree that installing Dovecot, and perhaps Postfix, and some other tools can be rather trivial, I switched to Google Apps when I was world-travelling with my family and my VPS provider back in 2008 basically disintegrated off the face of the earth.
Google Apps to the rescue. I created a Google Apps account, update my MX records and mail was restored in about 15 minutes (plus any DNS propogation time). This made Google Apps a huge win for me. It was supposed to be temporary, but am still using to this day.
But, I still have a Linux box or 2 that could handle email within 5 minutes if needed.
I used to run my own mail server. The main problem is spam: even with aggressive filtering, my mail was still 90% spam. Getting SMTP working is trivial. Getting useful mail is significantly more difficult.
As the article indicates the same is not always going to be the case with google.
With my email I spent about 6-8 hours setting it up a few years ago and haven't had to touch it since. Never had issues with spam or deliverability. Any decent hosting company should be able to provide the same, might cost more than google though.
