You could right that it is rare, I don't know how many times YEC results has changed the top 3 spots.
It's not rare for the YEC to shuffle the top 10 a little bit, but it's not the YEC in its entirety we're talking about here. It's one match, and we'll have to have two players within ~200 pts of each other, who both have chance of taking the #1 spot, and have them make the SFs and both lose there. Realistically, it's a once-in-a-million scenario.
Here's 2011 for you... before the YEC*:
1. Wozniacki 7395
2. Sharapova 6370
3. Kvitova 5970
4. Azarenka 5750
*Points from the previous YEC dropped.
1. Wozniacki 7485
2. Kvitova 7370
3. Azarenka 6520
4. Sharapova 6510
All Wozniacki had to do to secure the #1 spot was to win one RR match. Which she did, and nothing more. Kvitova won the whole thing but finished at #2 just short of Wozniacki.
But note how close Azarenka and Sharapova are. What happened that year was that Sharapova played two RR matches, lost both, and then withdrew with no chances of making the SFs, citing an ankle injury from Tokyo that had suddenly reinvented itself. Azarenka then had to play an alternate, Bartoli, in her 3rd RR match which was a dead rubber for her. In case you don't remember; she tanked it in three sets and couldn't care less. Was booed, deservedly.
Both Sharapova and Azarenka have people in their camps who know basic math and who can tally the what-if ranking scenarios. Neither of them (Sharapova and Azarenka) cared enough about the #3 spot to give a shit about the matches that would potentially have ensured them that spot. (Azarenka made the final, but without that she would have ended up #4. Sharapova could have secured the #3 spot by just playing her last RR match but chose not to).
This is the best example I can provide, because it really is just such an implausible scenario and nothing closer to a #1 vs #2 battle at the YEC has ever happened before. Sorry, but... they just don't care about the lesser spots. It's #1 or nothing.