There are very few cameras that could survive seven decades without completely reinventing themselves, but the Leica M is one of them.
While the rest of the camera industry moved from rangefinders to SLRs, then DSLRs and eventually mirrorless cameras packed with autofocus, subject detection, and increasingly clever electronics, Leica has spent much of the past 70 years refining essentially the same idea, as Mike Chudley has recently discussed in this YouTube video.
