The one thing that Fleets had going for them, that I think Twitter needs more than anything, is the fact that they are fleeting. Many people, myself included, are afraid to tweet something inane on main, lest we forget to delete it (or lest it be archived by a crawler), and have it taken out of context years later in a way that might damage our careers.

But it doesn't follow that "something is fleeting, therefore it is deserving of the rarest real estate on the screen." And the read-between-the-lines reason is that now it's Spaces that are more deserving of that real estate. "Ephemeral Tweets" are something that should be experimented with separately, perhaps as an option on a normal tweet and prioritized within the algorithmic timeline itself... but reusing the Fleets branding and presentation probably isn't the right way to do it!