I couldn't agree more with your idea. This is one of the reasons why I developed nostr-relay-tray and jumble. nostr-relay-tray can now enable non-developers to run a personal relay easily, and it can be accessed from the Internet without any configuration. The next version will support automatically pulling events from people you follow. Then nostr-relay-tray will become the personal caching relay you mentioned. And it can be browsed easily with jumble.