Whether cutting a long page in half helps depends entirely on what the half you remove was doing. The same act, halving the page, can lift it or sink it, which is why the results people report are so mixed. The cut isn’t really a length decision; it’s a content decision wearing a length disguise.
Cut the padding and it usually helps. If the page was long because it repeated itself, wandered into tangents, or buried its answer under preamble, then removing that material sharpens the page’s fit to the query and surfaces the answer faster. A tighter page that gets the searcher straight to it can climb, because you haven’t lost anything the searcher wanted; you’ve only cut what stood between them and the answer.
Cut the coverage and it hurts. If the page was long because it genuinely covered the query’s sub-questions, the depth and the cases and the explanation people came for, then halving it strips out the substance that earned the ranking. The page now under-answers what it used to satisfy, and it slips for the terms that depth was carrying. This is how it tends to behave, not a guaranteed result: what actually moved is the match between the page and the query, not the word count by itself. Thin has never meant short; it means content that doesn’t answer the query, at any length.
So the question is never “is shorter better.” It’s “was the half I removed padding or substance.” Read through the page before you halve it and separate the two: mark the parts that answer the query and the parts that only fill space, then cut the filler and leave the coverage intact.