A query and display loop is a very, very welcome addition. Since I've used query-loop plugins on virtually all my sites since at least 2011 I've been waiting for a core block solution.

From the old iThemes "LoopBuddy" plugin to Toolset's old Views plugin to Fernando Briano's old-school but remarkably sophisticated [catlist] shortcode-driven plugin to Beaver Builder's elegantly flexible Posts module this has been a solved problem in WordPress for more than a decade. It's long past time it was available in core WordPress. I'm looking forward to trying it out.

One major quibble though: "And, that is how it should be. Core WordPress should ship some basics while letting our community of theme designers showcase their craft."

Actually that's not how it should be. Core WordPress shouldn't leave it to the whims of 3rd parties to implement... well.. core features like thumbnail sizes. It’s particularly bizarre to hope theme developers add core interface functionality instead of sticking to design layers.

My very big concern is that relying on 3rd party developers means the core team will never bother refining the interface themselves. It's disappointing that your post seems to spin it that way. That's not how it should work at all! 3rd parties can and should build great variations and customization.

Annndddd.... not to put too fine a point on it, having just tried it with the Gutenberg plugin on a test site, the Query block is virtually unusable. And speaking of 3rd parties, I have to wonder if the core team ever took a look at the KadenceBlocks Posts block, the Ultimate Post Grid block, even a suggested block called "New Posts." All of which do a more credible, customizable job, with a more consistent (coughcoherentcough) interface than the (Gutenberg plugin version of the) core Query block.