No, sorry, that's not how Bitcoin works either. If the whole world used Bitcoin and the market cap of Bitcoin was over a trillion dollars, a 51% attacker could still only double-spend its own transactions. As long a public key crypto is secure, you cannot just re-write arbitrary Bitcoin balances into your own wallet even if you had 100% of the mining power. Therefore the incentive to attack Bitcoin is only as big as your own Bitcoin holdings, not the value of the entire market cap.