Well, what basically happened was that the developers at the Blender Foundation practically shelved Sculpt Mode to prioritise everything else for multiple years while the sculpt related projects that were supposed to happen got delayed or fell into the void, partly due to some drama with a previous dev who was supposed to work on Sculpt Mode that ended up leaving. It is only until fairly recently that Sculpt Mode has had any dedicated developers to code and review the changes.
While the rest of Blender got Grease Pencil 3.0, Cycles X, Eevee Next, Geometry Nodes, etc. Sculpt Mode only got a handful of quality of life features drip fed to us like VDM brushes and brush collection management while the bigger promised projects such as the Dyntopo rewrite and Multires rework are still left in limbo. Multires however got picked up again last year and is being worked on as we speak, but it takes time to fix all the issues and build in all the missing features that would enable more exciting features such as sculpt layers, vertex painting Multires support, a modernised texture management system, etc.
The situation is however different now when Sculpt Mode is no longer being treated like an afterthought, but it took years before that happened, hence the current lack of enthusiasm. The only reason Sculpt Mode has gotten this far is due to a lot of individual contributions by a handful of outside developers, one guy in particular who happened to lead the charge called Pablo Dobarro. He eventually worked with the Blender Foundation until he too left to do his own things some years ago.
I’m sure things will pick up again eventually. The Multires branch is looking promising, but it is basically a waiting game until those fundamental issues are fixed. I hope that they use the added income from the latest donations to invest more into Sculpt Mode and texture painting, since those have been needing consistent development for years.
Sculpt Mode is great though as it is. Easy to use, decent performance, and the access to other Blender features make it very flexible, especially with the addition of Geometry Nodes that did actually upgrade the capabilities of Sculpt Mode substantially. Made a tilable texture modifier for micro details last year for instance based on my needs. It is not a full ZBrush replacement, but add-ons can cover most of the holes missing. I still use Blender for sculpting because I like it more.