'why not get a dedicated professional to handle devops on your team'
It sure is easy to write that, but the reality isn't as rosy. I've gone through the process at two companies to try to do that, interviewing ~50-80 people and it has been a nightmare. It is really really difficult to find quality devops people. Again, this makes PaaS like AWS, Heroku and AppEngine a lot more attractive. They are betting their entire business on being able to hire good devops people, so they tend to attract better talent.