It's a complex topic.
The core philosophy behind it, in my perception, is just that indexing is seen as secondary by Itch. It is nice to have. But it is not essential. Five minute fame for being briefly visible on the most recent page is not gonna change the success of practically all released games. So why bother with such features. Or make indexing a priority, when there are other support issues.
Imho the most effective way to prevent unnecessary support requests would be to change the docs and if there are, other places where a time frame for indexing is mentioned. It causes expectations, that are not met and leads to frustration and the limbo of uncertainity, since the docs also do mention the possibility of intentional non indexed status.