In Dutch we have the word "scorebordjournalistiek". Bit hard to translate into English (I don't think there's a real equivalent), but it means drawing up conclusions purely based on numbers rather than looking at the actual situation. It comes from the world of sports, where for example a (football)team might win 1-0, but that doesn't necessarily mean it was the better team (it was merely more lucky/efficient than the other team).
With large lists like the Box Office and TSPDT 21st Century the numbers for 21st century films will rise pretty quickly, but these lists cover rather small (but popular) niches of the current film landscape (popular commercial + popular arthouse). You're out of luck if you want to explore films for niches not covered by these bigger lists.
But to be really clear (and I'll just speak for myself now), the 21st century could really do with better/broader representation over different genres, niches, countries and movements on ICM.