Nope STV is not so good, it still falls to Arrow's Impossibility Theorem which applies to every single rank voting system.

Sure, first-past-the-post is horrid, but if you expend political will, time, power, energy, money to reform the voting system, it's a tragedy to replace a horrible system with a bad one when we actually know of a good one. We will not get infinite, costless resources and chances for voting reform.