[thisisit]

That is assuming a 51% attack is only about double-spends. There are other attacks which can be done without trying to double spend.

Still it this exact belief in math that will become a self fulfilling prophecy and keep bitcoin afloat way past someone executing 51% attack.

[sowbug]

Right, my reply simplified the issue.

But generally, it's a fair generalization that if step #1 in taking down Bitcoin is acquiring >50% of mining power, most rational actors will go off-mission and decide that step #2 is mine Bitcoin, not screw with it.