Ask HN: Why is there no good travel organizing app?

Has anyone else struggled to find a great app for trip planning? It seems like a common pain point:

- Search/discover activities/attractions in advance. - Build a flexible itinerary (not rigid time slots). - Share the final plan or reviews post-trip.

Plenty of apps do pieces of this, but why is there no seamless, user-friendly solution combining all three? Is it a technical challenge (e.g., dynamic routing/data aggregation), a market gap, or just undervalued by builders? Curious for takes from travel-tech folks or frustrated travelers alike.