It’s not really so clear cut. Perhaps if a 51% attack let you fully steal coins yes. But there are only specific things a 51% attacker can do, and even attempt

It’s not really so clear cut. Perhaps if a 51% attack let you fully steal coins yes. But there are only specific things a 51% attacker can do, and even attempting to pull off the attack has game-theoretic impact on the price if Bitcoin. The more practical attacks are greedy miner type attacks which just boost a large miners win rate. The 51%-esque chain rewriting, double-spending and transaction censorship stuff is a different story. What you can definitely say is that economically the profitability of the block reward and transaction fees will drive new entrants into mining. As BTC price increases the willingness to spend more on mining (wasting electricity) increases. But the block reward also halves now and then to reduce the value of new blocks and prevent the waste from getting absurdly out of hand.