Starcraft is important but IMO it's not about APM. But build order, at start of each game, there's a series of steps you need to do like the optimum workers to build, to mine Vespene gas; at which time to send workers to build expansion base, build marines/zerg's etc. And adjusting your strategy depending on map, other races on map and opponent style. Translated roughly to non-player's words, playing Starcraft is not…
All that matters is you mine exponentially by always building a worker when you can, and never getting supply capped, and spending your money.
A grandmaster can beat a platinum simply by building 10X more primary units than their opponent. There have been demos of this online.
It's true you can "perch" yourself in Diamonds or Masters with a single cheesy build, but if you want your rank to withstand patches and new releases, then you have to master the fundamentals - probes and pylons.