It's been that way for a few months and this is Chrome only major version update since it arrived in the Play Store.
But that is changing, Google has said that it hopes to bring Chrome for Android in line with the desktop and Chrome OS versions sometime early next year.
It also made another interesting reveal, a dev build of the upcoming Chrome for Android will be made available by the end of the year.
It won't be a one-off thing either, once Google gets Chrome for Android up to date, it plans to update the browser across all platforms at roughly the same time.
The best-case scenario would be a new Chrome for Android landing every six weeks. This should also affect Chromebooks, which sometimes lag behind the desktop version of Chrome and skip entire versions on occasion.