Yeah, claims that it can be faster than CH are very suspicious. CH guys are very good at their craft, they spend hundreds of hours optimizing one single small detail.
Yeah. I don't think PG could even come close. Column-oriented is fundamentally different, and pairs well with all the SIMD acceleration ClickHouse is also doing. There's just no comparison. If a Postgres rewrite came close to that, it must've sacrificed something else.