When you purchase a Quicken subscription from Quicken, Inc, I believe that you are automatically agreeing to auto-renewal, but it can be turned off by going to Quicken.com and signing in. Auto-renewal is always MSRP for renewals, so no bargains there.
Yes, you could have purchased from a retail seller (make sure a reputable one though) and use it to extend your subscription.
The year designation of Quicken is purely a marketing ploy, subscription is subscription and as long as it is active, it is eligible for program updates, whether automatic or manual.
See this thread for what happens if your subscription expires: