I made the switch to mobile friendly themes and setups a while back when Google decided to make it a ranking factor. Google has decided to give the mobile friendly sites a rankings boost in mobile results if they are mobile friendly, so now this is a priority for most website and blog owners.
Since I have many that are WordPress websites just switching to a theme that was mobile friendly was all that was needed. The ones that I didn't want to change the theme on I just added a mobile version of the site.
Google dictates a lot of the changes that webmasters have to deal with so making the change to a mobile friendly version of websites is no longer an option but a requirement if you want to keep your site as high up their rankings as possible.
