RFs are nice and especially if you like to shoot wide lenses they tend to be more accurate than SLRs (although
I do have a split prism screen for mine, which helps a lot). The P67 is nice for portraits though, longer lenses are tricky on rangefinders. If you are a masochist and like to shoot wildlife/etc on MF/LF, the P67 system is by far the most comprehensive and affordable.
Portability is really the problem with the P67. I find myself drawn to cameras that pack a big punch in a small package and the P67 just is a physically very large camera. I like my Fuji GS645 folder for travelling and would like a GF670, I snagged a 120-converted Kodak Medalist (heliar-type lens), and I have been trying to get set up with a compact 4x5 setup. I just got that Polaroid and I have some Grafmatics for it, maybe someday I'll grab a Pocket Gowland to go with it.
I wouldn't mind a G690, but the lenses are fairly scarce and expensive. It is also a surprisingly big camera (assuming it's like the fixed-lens versions). Like, it doesn't look that big in pictures, until you realize that the camera body is about a 50% larger diagonal than your iphone plus. It is actually comical in person, not much smaller than a P67 at all. But, much lighter than a P67, which helps.
Leica is too expensive for my blood although I do have a Nicca body and a Nikkor 28/3.5 LTM for it. I particularly liked that lens on the Nikonos and wanted a copy that didn't have the underwater mounting/scale focus. For really low light shooting I like the Yashica Lynx 14E and the Olympus XA with film pushed to 1600. The 14E is the fastest lens on a fixed-lens RF ever and has a leaf shutter to reduce vibrations, while the XA has a wide lens, a piezo release, and a leaf shutter. Both do well with handholdability at slow speeds. The Olympus XA can be modified to support 1600 by spinning the paper disc over the meter one stop further so that all speeds read one stop faster, the 14E is full manual.
I mostly don't do 35mm SLRs anymore. Digital does that stuff better, so I do digital for that (I can adapt old lenses to my NEX camera) and MF/LF for fun. Easier to scan too, 35mm really needs a pretty decent scanner to get full quality, or wet printing. Trying to get set up for a basement darkroom, too many projects too little money.
I don't mind GAS. I admit I like the collecting too, it's a hobby. And I don't mind having "special purpose" lenses or cameras that do one niche thing for me. It's nice to have the right tool for the job.
Yeah, the late 2000s were a wild time for cameras. All the pros were dumping their film gear for digital, the financial crisis caused people to dump grandpa's old camera junk for a song and meant little competition, and hipsters hadn't latched onto film gear yet. I picked up my first 6x7 (non-MLU) for $300... with a meter prism and three lenses. That stuff has roughly tripled in value since those days, I think.