I agree that Iran apparently prefers not to escalate (although it’s hard to say whether its attack was deliberately limited or simply couldn’t penetrate Israel’s defenses) but this is consistent with Iran’s strategy of acting through proxies. Iran doesn’t want a more direct confrontation with Israel because the status quo allows it to damage Israel much more safely and cost-effectively than it could by fighting directly. In this context, effective Israeli action against Iran requires escalation because otherwise even defeating the proxies is still a net loss for Israel, and so killing the specific Iranian leaders responsible is a good strategy because it makes hostile action against Israel much more costly specifically to those instigating it.