Cryptocurrency Mining

Seems too good to be true (easy investment at a decent payout).
-am I right in interpreting that mining, say, bitcoin, is as safe as the existence of the currency? As in, if you can't make money mining, the currency is completely folding for good?
-I have 10k I was to spend on computing power. Does ratio of bitcoin payout go up if the price of bitcoin drops, to compensate? I was thinking it'd have to for the currency to remain strong, or to not fold.