The simple reason for limiting calendar length is that without any limit, the calendar file would be infinite in size. That wouldn’t work. The current defaults were selected so that they fill almost all needs, are fast to generate, work with all calendar applications and cause no issues.
Your calendar does not end after 6 or 12 months. Instead, it is updated automatically. So 6 months from now it will still show 6 or 12 months into the future, relative to that point in time. Your calendar will not end (at least not before your subscription period ends). Each calendar is updated every day, or at least every week.
Long time windows can cause multiple issues:
If you still want to see further into the future you can do this for most calendars. Please see How do I make my calendar subscription show further into the future? for details.
Updated Wed, 08 Feb 2023 12:08:23 +0000 UTC