Search is narrow, used occasionally to find external information. LLMs are the single most general-purpose tool in existence. If you're using them to their full potential, you end up relying on them across writing, planning, coding, summarizing, etc.

So even if the per-query or per-token cost is lower, the total consumption is vastly higher. For that reason, while it may not be a fair comparison, due to people looking at it from the perspective of personal economics, people will compare how much it costs to use each to its full potential, respectively.