It's not the expected price per se, but the expected payoff of the investment

We may never sell at 5000% because we're looking for 10000% so we might ignore that price until it either hits our sell point on either side. Either 10000% gain or 90% loss

The value of the investment is then our expected value, but also decreased by risk-free rate for every year we expect to hold to make 10000% profit and divided by half for the probability of 50%

So if we expect to hold for 100 years on average to achieve that price, it's not a good investment because you can just buy bonds that yield 5% to achieve that return (131.5x after 100 years)

But if we expect to hold it for ten years, it becomes attractive