Maybe, but what if you bet $4800? You still have the most unbet chips, so if everyone wins or everyone loses, you are still BR1. However, if villain 1 & villain 2 both double for max and win, you can still beat them both without needing to bet more than your original bet. (V1 = 20,200; V2 = 20,300; Monkey = 20,500). Since you act last, you'll see what your opponents have after doubling. You can stand on a good pat hand, or hit more than once if needed, but you won't HAVE TO limit yourself to one card by doubling. Plus if either V1 or V2 are able to split and double on one of their splits, the most that can be wagered is by V2 at 10,300. A win on both splits gives him 20,600. You still advance with 20,500.
But what about Blackjacks? Suppose V3 AND either V1 OR V2 gets a blackjack and you and the fourth player lose. You would still have the second-most chips at 10,900. V3 would have 10,750. The fourth player would have, at most, 5,300.
Now, I just realized this analysis took me over 45 minutes to figure out, double-check, change and re-check. And that's without being in the heat of the battle. I doubt I would even think this deep at the table, let alone be given enough time to work it out. But these are great exercises and I really appreciate being able to work out my answer and then read answers and responses from others. Even if my reasoning here is way off, it's still very helpful to try. And I don't mind hearing that I'm wrong. I would much rather learn that I'm wrong this way than through the painful self-analysis following another losing round in a tournament!