There's actually some really cool math developed about situations like this one. Large deviation theory describes how occurrences like the 1,000,004 red / 1,000,000 blues one become unlikely at an exponential rate and how, conditioning on them occurring, information about the manner in which they occurred can be deduced. It's a sort of trivial conclusion in this case, but if we accept a principle of maximum entropy, we can be dead certain that any of the 2,000,004 red or blue draws looks marginally like a Bernoulli with 1,000,004:1,000,000 odds. That's just the likeliest way (outside of our setup being mistaken) of observing our extremely unlikely outcome.

What getting a ratio of 1000004:1000000 tells you is that you're looking at the wrong hypotheses. If you know absolutely-for-sure (because God told you, and God never lies) that you have either a (700,300) bag or a (300,700) bag and are sampling whichever bag it is uniformly and independently, and the only question is which of those two situations you're in, then the evidence does indeed favour the (700,300) bag by the same amount as it would if your draws were (8,4) instead of (1000004,1000000). But the probability of getting anything like those numbers in either case is incredibly tiny and long before getting to (1000004,1000000) you should have lost your faith in what God told you. Your bag contains some other numbers of chips, or you're drawing from it in some weirdly correlated way, or the devil is screwing with your actions or perceptions. ("Somewhere close to 50:50" is correct in the following sense: if you start with any sensible probability distribution over the number of chips in the bags that does allow something much nearer to equality, then Pr((700,300)) and Pr((300,700)) are far closer to one another than either is to Pr(somewhere nearer to equality) and the latter is what you should be focusing on because you clearly don't really have either (700,300) or (300,700).)