[Mindwipe]

I don't think it's that they've entirely ditched FB, but FB is genuinely terrible at surfacing event invites. It would prefer you to have to scroll through a bunch of irrelevant garbage in your feed that it had "recommended" instead so the product team can high five themselves over badly designed engagement metrics rather than worry if the users don't actively despise their product.

[Chilko]

Yep I second this, I usually find out that I've been invited to an event when someone makes a post in the event, and often not from the event invite itself.