Oakensnaf,

Your presenting a personal situation as mathematical argument and 'evidence'.

Probability is what turns the tide in any Zero sum game. The more you play it the more you will lose. If you can create an edge [odds in your overall favour], then the opposite of course applies.

If you have a 2/1 odds [against] of crossing a paddock with an angry young bull in it and only do it once, you have probability working for you the best it possibly can, do it 1000 times and you will be gored to death for sure on one of those trips because probability [not odds] worsens with each trip. The odds of course remain exactly the same with each trip. Odds are not the same as probability and confusing the two is quite common.

What a maths site has to say on the subject:

A jar contains 1 blue mable and 3 red marbles.

Odds are expressed as the number of chances for (or against) versus
the number of chances against (or for). So, since there is 1 chance
of your picking the blue, and 3 chances of your picking red, the odds
are 3 to 1 AGAINST you picking the blue. For odds in favor, we just
reverse them. The odds are 1 to 3 IN FAVOR OF you picking the blue.

This can be a little confusing, so I'll say it again. If you express
odds as AGAINST, you put the number of chances against first, versus
the number of chances for. If you express odds as IN FAVOR OF, you
put the chances for the event happening first.

Note that this does NOT mean that the probability is 1/3 for or
against in the above example.

To convert odds to probability, we have to ADD the chances. So, if
the odds against a horse winning are 4 to 1, this means that, out of
5 (4 + 1) chances, the horse has 1 chance of winning. So the
PROBABILITY of the horse winning is 1/5 or 20 percent.

And put another way:

Lets first show the difference between probability and odds in another way, just
to be sure we're using the same terminology. The probability of an
event is:

------------ (Chances for)
P(x) = ------------------------------
------------ (Total chances)

So, for example, the probability of drawing an ace in a single deck of
52 cards is 4/52 = 1/13 (or about 0.077 = 7.7%).

Odds, on the other hand, are given as:

(Chances for) : (Chances against)

Of course, (Total chances) = (Chances for) + (Chances against), so
we can determine (Chances against) as (Total chances) - (Chances for).
The odds of drawing an ace in a deck of cards are
4:.....(52-4) = 4:48 = 1:12.

It's easy to work out from the above that for each chance [bet] you take when the odds are against you, your situation is worsening because of negative probability.