So you say, but my guess is that you aren't privy to complete information about the markets and what the miners are actually doing.  Unless you're a serious insider-bigwig (and you may well be, who knows), there's an awful lot of guesswork involved when trying to figure out how to play the crypto market. 

Bitcoin basically comes down to supply and demand, unlike the stock market where business factors have a huge influence on a stock's price.  But in that supply and demand there are myriad factors dictating demand--and to a lesser extent, supply.  I've always thought of it as an enormous multivariable calculus problem that keeps changing.  So your claims to use logic and numbers are laudable, I'm skeptical as to how much they can really help you as a trader.  But I could be completely ignorant and wrong.

As to the question posed in the title:  $13k wasn't sustainable because the price curve was way too steep.  Too much money poured in, too much speculation happened, and too much selling went on after bitcoin hit that mark.  The only way bitcoin is going to stick around at $13k or above is if the price/time slope is a lot more shallow.  The bitcoin market doesn't tolerate spikes very well, as you may have noticed. 

But hey, at least it didn't crash back down to $3000.  I'm totally cool with $11,350 (which is where it stands as I type this).