@ F_Quill you have lots of info to digest in the thread and would like to share my thoughts.
I got involved in the beta version of Lightroom in late June 2006, the app was released in Feb 2007.
The first thing that captivated me was the fact the application was working towards eliminating the need to store the editing info in xmp sidecar files. It was in the early days of using applications that the main function was rendering RAW files created by Digital Cameras, at that time all the apps that were available created sidecar files to store metadata data and editing info since this info was not written to the raw files.
ACR was the Photoshop plug-in that provided this function for Adobe application purposes, Lightroom was being designed to not store the data in a sidecar but to utilize a Catalog Data Based file to store the info and edits. At the time I was using three other raw processing applications which also created there own sidecar files. It was a pita for sure so when Lr was launched I decided to adopt Lightroom in preference to the other apps.
The longtime users of Photoshop / ACR were comfortable with their option and did not choose to adopt the Lightroom Catalog based workflow and many remain with this choice.
My view is Lightroom is an option to ACR / Bridge as the Develop and Library Modules provide these functions and some more you have the Print, Web, etc that provide more sharing functions.
Lightroom in this respect is a full stand alone application that provides most of what a photographer requires. It does not possess the advanced features of Photoshop that are essential for graphic artists and the like.
Lightroom does not require you to have any other Adobe application installed for it to function.
You can see the apps that I use in my signature info but my workflow does not include the use of xmp sidecars or DNG files.
Lightroom is not a good mix and match with ACR / Bridge. Lightroom has an option to write data to the file so it can be share with ACR / Bridge, however they cannot read or write to the Lightroom Catalog file.
If you are happy with ACR / Bridge that's fine.