Yeah, you’re right. His inconsistency can be frustrating. The prominent view before seemed to be that it’s because he’s “not clinical enough”, which can occasionally be the case, but as you say I think it’s more to do with the balance of the Chelsea team. Sometimes it seems like he can tell the players around him aren’t good enough. He’ll score tons when he eventually goes to Madrid.
That season where he downed tools was an anomaly I think. He was injured throughout but expected to carry the team, despite getting fouled more than any player in the league (the infamous Mourinho and Dr. Carneiro incident happened because Hazard was fouled and wanted to come off by Mourinho wouldn’t let him: he was also close with Carneiro so was likely pissed off at Mourinho more than others).
He seems a good egg off the pitch as well. I love the appropriate disdain with which he treats Geoff Shreeves.