And more generally, I think a lot of people make a misjudgment in assuming that actors in the bitcoin ecosystem will behave with only very short-term focus. Tim Swanson (@ofnumbers) is particularly bad about taking these absurdly narrow views and spitting out blog posts full of "analysis". Unfortunately his analysis is often not particularly useful because his assumptions are broken.
Exactly, a particularly absurd attack is that bitcoin will fail due to mining centralization and this centralization will enable miners to act poorly. The reason this is absurd is the more mining becomes centralized the more capital each miner has committed to the project, which means miners will act with more of a long-term mindset as they become larger and commit more capital.
But even if this wasn't the case, the incentive structure of mining means that even IF miners took a short-term only mindset (which is illogical), incentives still encourage them to only mine the longest chain.
To break bitcoin would require a large 51% entity who could operate without economic concerns or constraints, i.e. they have billions in capital to destroy specifically to attack the project, expecting a full loss if successful. Only a government could try to pull this off at this point, the private market will not.
The underlying assumption here is that (Bitcoin) economics is the only motivator. If there exist entities that both care about Bitcoin and want to end it (and have sufficient motivation and resources), than this argument fails. There may well be much cheaper ways to end bitcoin than a persistent 51% attack, (and such a persistent 51% would not be guaranteed to succeed anyway), so it is probably in the 'good enough' category. It is not in the 'safe' category (though Andreas A. disagrees with me on this).
broscience FTW! 
