No they are not as flexible
I would view the regard the rangefinder as unparralled for candid or journalistic photography that can be accomplished with very wide thru short telephoto. If however you start needing lenses longer than 90mm, certainly longer than 135mm range finder cameras take a definite backward step. A 135mm lens on a range finder camera is very hard to do sophisticated composition with since it ordinarily involve a very small portion of the viewfinder and is more difficult to achieve focus with. With a rangefinder you have the advantage of seeing elements outside your photo area but you do not have the ability to do depth of field preview. It is possible to attach ground glass viewing to rangefinder cameras that take the Leica M mount thru the use of the visoflex III which is no longer made but available used. Many of the Leitz lenses from 65mm and longer were usable. Diaphram operation was manual. I do not have a clue if the current Leica lenses offer this feature. This, the Visoflex, was capable of first class resilts for nature, scenic and still life work or anything else where a 35mm format was usable and the subject would stay put. It is today pretty much very outdated.
For myself, I find that if I have more than one camera system one of the two becomes an orphan hidden in the closet and the other gets regular excercise.
Since so little of my photography involves people, my granddaughter excepted, and because I like using 35mm cameras I am working exclusively with a 35mm SLR and my 4 lenses and Mamiya RZ67 body is resting.
So then the rangefinder is nice but specialized equipment that is unbeatable for a narrow field of work and somewhat or very much comprised for all of the rest.