This is of course driven by the desire to have predictable and steady revenue. It's easier to plan and resource, but I would also say it's easier to coast for a mature product. If you need to push a release to generate a revenue influx, you would be more motivated to deliver. However, in the case of a mature product each feature will probably have diminishing returns. For the user this makes the incentive to skip an upgrade tempting, so locking them into a sub model while there's still leverage is a strategy.