DSLRs never stood a chance when mirrorless cameras arrived. Not because mirrorless cameras were any kind of breakthrough in imaging technology, but because they had the entire weight of the camera marketing industry behind them.
Don’t get me wrong. The best mirrorless cameras have a lot of advantages – in certain situations. The more compact design (i.e. no mirror) makes them ideal for small system cameras, while the always-on live view makes them perfect for video where mirror-up operation was always a bit of a kludge with DSLRs. The best travel cameras are almost all mirrorless (or compacts).
