Even $100,000 would kill it. If 1 sat (or even 100 sat) == $1 then the fees would grind the system to a halt. The fees would be so high relative to the amount sent, that it wouldn't be worth it. From an investment perspective 1 sat==1$ is a nice round number. From a users perspective, only being able to buy things divisible by 1$ is crap.
Bitcoin price is not limited by cost of the fee but by energy to secure network. Right now we spend less then a percent to secure Bitcoin network. With 20 times higher price there will be 10% of all energy used. Increase of energy price will definitively help. And I dont believe we will ever again have this cheap energy as of now.