I noticed the same the other day. I am actively searching for a 27 inches monitor recently. I am torn about the decisions if I should wait for Apple to release new monitors(not sure if it's gonna happen soon and i am a sucker for Apple products) or just buy a used LG ULTRAFINE 5K...
I'm in the same boat. I need to order a new monitor before the end of September and wanted one, probably a 24" 4K or 27" 5K that works well with my 2018 MBP. The Ultrafine are the ones that are supposed to do that, right? You would think that Apple is replacing them since they are out of stock, not to mention the years-old thicker bezels.
But I may have to resort to ordering a 27" UHD USB-C such as the HP Z27.