guàn names a Daoist temple and shows up almost only in 道观 and 宫观. It also covers an old palace watchtower or viewing platform. Everyday senses of looking, watching, and worldview all take guān instead.
见 is the indexing see-radical, a person with an eye above, and carries the whole meaning: 观 is looking with intent, observing or contemplating. It pairs with 视, 觉, and 览. The simplification kept 见 because seeing is the core act.
又 on the left is the modern simplified replacement for the traditional 雚 heron phonetic in 觀. The reform swapped a tall bird graph for the simple hand shape purely to cut strokes, so it carries no etymology here, just a marker that distinguishes 观 from 见.
