The year is actually visible if it’s not the current year. Often times, you’ll also have the option to place your mouse/cursor over a date or time to get a full view of the timestamp.
Here are some examples of how the year is displayed for older posts in various places:
Forums Homepage Latest section which shows the first post and last post timestamp
Search Results page
Topic Post/First Post of a topic
If there is another place where you don’t see the year, please let us know, and we’ll look to make that more user friendly.