The chart is misleading for most cryptocurrencies.
The "1h Attack Cost" is calculated from the rentable hashrate from NiceHash, but you should pay attention to the "NiceHash-able" column that says how much hash you can actually rent.
While you'd think you could attack Ethereum for only 1.5 million dollars, you can only rent 7% of that hashrate, so you can't get the required >50% you'd need to pull of the attack.
The "1h Attack Cost" is calculated from the rentable hashrate from NiceHash, but you should pay attention to the "NiceHash-able" column that says how much hash you can actually rent.
While you'd think you could attack Ethereum for only 1.5 million dollars, you can only rent 7% of that hashrate, so you can't get the required >50% you'd need to pull of the attack.