I personally think that if you are going for a huge, long shot parlay, you are much better off just having one or two legs worth of big odds.
Each leg that you add essentially introduces another variable of uncertainty, and you'd have to have something ridiculous like 10, 20 legs of 1.2x bets in order to achieve the long odds that you want. That sort of thing simply becomes impossible in practice.
In contrast, 1 or 2 big odds bets can occur in unison in a black swan event, and their odds are generally more attractive.
In fact, the odds of a single bet are not important, their number is important (and the fewer the number of bets, the better). Here's a basic example (you can plug in any other numbers and do the calculations):
On a coin toss, the odds from the casino are 1.95. There is a 50% chance that you will earn 95% of the bet. It turns out that on average you will lose 2.5 percent of each bet.
If you make a multi-bet on a two-coin toss, then on average, you will lose almost 5 percent from each bet (your profit from guessing will be only 3.8025 of your initial bet).
- the higher the number of events in your multi-bet, the lower the mathematical expectation of a profit.
And yes, one big bet is much more profitable than any multi bet.