A rangefinder is a higher quality camera than an SLR ever was and a full frame mirrorless probably has better quality than a DSLR, in both cases because it's easier to design lenses for them. A medium format camera can be better than all of those.
DSLR means: it's digital, it uses one lens, and the visor image comes from the same lens that goes to the film, but reflected on a mirror to your eye (probably through a pentaprism, but that can vary), so you can see the same image that will be captured in the sensor.
A rangefinder is a camera where you look... through a rangefinder. It's a visor independent of the film/sensor, like a classic Leica. That means that the image you see is not exactly the same that will reach the sensor/film, as it will go through a different optical system. There are digital rangefinders like the M series Leicas.
Mirrorless means, it doesn't have a mirror to send the image to the visor. The typical mirrorless cameras nowadays get the visor image directly from the sensor, you don't look through a rangefinder. A rangefinder is mirrorless, but not every mirrorless is a rangefinder. Most digital mirrorless cameras aren't rangefinders.
A rangefinder (or mirrorless) camera is not inherently better than a DSLR. Mirrorless cameras can have simpler optical designs that achieve more quality easier, but there are better and worse cameras in both sides.
You said:
- A rangefinder is a higher quality camera than an SLR ever was
- a full frame mirrorless probably has better quality than a DSLR
- A medium format camera can be better than all of those
- rangefinder only means it has a rangefinder. There are Yashica Electro, Argus C3, and there are Leicas. Most rangefinders are medium/low quality
- well nowadays, maybe, but not necessarily. But we can generalize a bit in that case
- A medium format camera can be mirrorless, DSLR, rangefinder... so it can be in any of those groups, so we cannot compare it just like thatThis does not mean anything at all. The comparison is total nonsense.
>and a full frame mirrorless probably has better quality than a DSLR
No. DSLR and Mirrorless camera differ how the viewfinder works. Generally Mirrorless cameras are newer, but ranking them for quality is totally nonsensical. This is independent of the size of the sensor.
>A medium format camera can be better than all of those.
You are comparing totally different things. A full frame Camera can be Mirrorless or a DSLR. There is no comparison to be made here. You are totally confused about technology and terminology.
I don't think image quality is the end all be all of a camera, but is what amateurs think the purpose of an expensive camera is.
Why are you talking about prices, when you were making absolute comparisons about what is better?
It is true that people these days associate the DSLR form-factor with professional photography, despite the heavy use of rangefingers by those such as Robert Capa etc not that long ago. And it is also true that both rangefinders and mirrorless ILCs avoid the need for retrofocus designs which in theory should make for higher-quality lenses at the same weight, or similar quality and a lower weight.
As for "better" this is often a matter of preference and it's okay for people to have different preferences. For me personally, I wish there was more experimentation in ILC form factor, it seems most (with a few notable exceptions) ape the pentaprism hump even if they don't contain one.