Is it just me, or is this graph (first graph in the article) completely unintelligible?

The X-axis being time is self-explanatory, but the Y-axis is somehow exponential time but then also mapping random milestones of performance, meaning those milestones are hard-linked to that time-based Y-axis? Then individual models are mapped onto it, indicating that the Y-axis is some abstract performance metric, but none of it makes sense in relation to the property of time? What?