Gmail and other big providers tend to consider new domains to be spam until they've proven otherwise. Can't prove otherwise until you've been up and running for a while. Catch-22. The way out of that is to host with an existing provider for a few years.
Does it cut down on spam? Perhaps. Does it favor existing providers like Gmail? Yes, definitely.
Honestly, hosting email has long been difficult to setup, and all the more so if you don't want your box to be a spam host within three seconds of plugging it in.