I have been following this thread with a confused expression on my face. The A7CR and Fuji X100vi are two entirely different cameras. The Sony is roughly twice the price of the Fuji and has a FF sensor, as opposed to the Fuji’s APSC sensor. The Sony is a full function, interchangeable lens camera while the Fuji is essentially a fixed lens point and shoot, and in that regard, a better comparison would be between the Fuji and the Leica Q3. It should be obvious to anyone who wears pants that the A7RC is not pocketable, and likely was not meant to be. If the OP wants a purely pocketable camera he/she might be better served by searching for a used Olympus Pen F. It has interchangeable lenses and is as close to a pocketable camera as I have ever seen … I happen to have one in my collection, so I have first hand experience.
I should state that—among a collection many different cameras—I own both an A7RV and an A7CR, the latter is carried in a small shoulder bag, while the former is also carried in a larger shoulder bag. I’m not convinced that carrying a camera—other than one’s smartphone—in a pocket is a good idea from the perspective of longevity. But that’s just my opinion, and others obviously feel differently, as they are surely entitled to.
The PEN-F isn't any more pocketable unless you're using the 20/1.7 or 12-32... The 12/2 is the size of the Sony 24/2.8 G, a PL25 is the size of a SY 45/1.8, even UWA zooms across both formats are similarly sized... It's not until you get to superzooms or teles that M4/3 leverages much of a size advantage these days.
Not even all the superzooms I would say... The Tamron 28-200 is no bigger than the great 12-100 Pro and is faster on the wide end (although lacks an OIS). An A7C+28-200 combo is about the same size as the OM5+12-100!!
Yeah true, I meant something more like the 14-140, or teles like the 75/1.8, 35-100, 100-300, or PL50-200. You could still rightly argue that two of those have been sorta size/weight matched on FF, just not on E mount; eg the L mount Panasonic 28-200mm f4-7.1 (plus a little cropping on any high res body, it really is very close to the 14-140 in size/weight), or the RF mount 100-400mm f5.6-8 (plus a little cropping again, not much heavier or pricier than a 100-300).
The advantages to smaller formats are dwindling, somehow I think M4/3 fell way behind when it comes to UWA zooms where it
could still have an advantage, but it really doesn't. I used to love my PL8-18, superb build, it's the size/weight of a 16-35/4 G tho. The 7-14/4 isn't significantly smaller (tho wider) and the 9-18 (which I did own/like) is woefully long in the tooth for the price. Meanwhile APS-C caught up and lapped M4/3 there with zooms like the 10-20/4 G and 10-18/2.8 DN.
Then to top it all off the M4/3 manufacturers stopped making any new bodies smaller than an OM-1 or G9 II, basically as large as your average A7 (larger than an A7C)... Gone are the GX# & PENs let alone the GM/GF/GX###.
So yeah, I can see the argument for the X100 because of the short lens, but searching for a used (and probably overpriced) PEN-F? Yeah that's not gonna be any smaller than an A7C and some small FF primes, cheaper
maybe, if you get a good used deal on everything. Emphasis on the maybe, after 2 zooms and like 8 or 9 primes I paid less on average per lens on FF E mount than I did on M4/3. The only one where I paid about the same was the 35/1.4 GM vs the 17/1.2, coincidentally also about the same size (GM is heavier tho).
For a few key teles I could see the argument, but it's getting less reasonable every day. Only reason I'm attached to my GX850 + 75/1.8 is because I got a great deal on the latter and the body really is smaller than anything out there.
An a6400 + 90/2.8 DN is not far off and would be more capable despite being 1/2 a stop slower by equivalence (taking cropping into account). It's a sad state of affairs, I'd say the 70-350 G was always a better deal than the PL50-200 (or any FF tele at the and price if one is serious about shooting those FLs, but those will be larger). So I've basically made the case for any/every of the few M4/3 lens options I cited still made sense size-wise.
It wouldn't be quite so grim if there were any legitimately new small bodies since 2018/2019, but the E-M5 III was the last and even that was generally agreed to be overdue. At least Fuji has kept up with the X-S even if not the X-E or X-Pro.
I
hate throwing dirt on a format because I think if equally developed to their full capacity they could all have certain advantages, but yeah no M4/3's are dwindling and there's no great advantage at super long FLs either.