I simply cannot imagine lounge status "until end of year plus the following calendar year" is of much relevance. IHG loyalty knows that people tend to have fairly sticky stay patterns and are gonna make the lounge pass in 14 out of 15 or 8 out of 8 years. Of course, that's not universally the case but sort of the rule rather than the exception. Investors which raise the issue of lounge pass duration can simply be brought up to speed on basic facts of loyalty by IHG.
Instead, I can imagine raising the bar for the annual lounge pass milestone can be something considered much more seriously. Those of us in hotels all the time know how strong is demand. Business demand has been stronger than they must have thought it would be when they introduced the lounge milestone. And, of course, leisure demand has turned into a "higher for longer" story as well.
Thanks for sharing what you've heard! In any case, I give more credit to the higher-threshold gossip than the shortening the lounge pass validity gossip.