For some people, it's the availability of one or two features that are crucial to their shooting that pushes them to a mirrorless system. There are far too many to go into here, but even if we just focus on one, namely the silent shutter, we can see what kind of a practical difference this can make.
Anyone frequently shooting in conditions where discretion is key will appreciate a camera's ability to shoot silently, not just quietly. For years, DSLRs have offered 'quiet' or 'silent' shutters, which work by breaking up combination of physical actions that take place at the moment of capture so that they are less obtrusive. While these options aren't completely without merit, the fact that the camera still needs to swing up a mirror and open a close a physical shutter means that they haven't been able to come close to the genuinely silent shutters found on many current mirrorless models.
The reason for this is that mirrorless cameras are typically designed with both mechanical and electronic shutters, whereas most DSLRs only offer the former. Although electronic shutter have their drawbacks – they are not suitable for moving subjects or use under some types of artificial lights – the fact that they operate silently makes them far better suited for weddings, events and for wildlife, and in any other genres where making as little noise as possible is critical.
Another advantage of electronic shutters is that they allow much higher shutter speeds than mechanical ones. Whereas many DSLRs are limited to top speeds of 1/4000sec or 1/8000sec, it's usually possible to access shutter speeds of around 1/32,000sec on even cheaper mirrorless cameras with these electronic shutters.
DSLR manufacturers have, however, fought back in recent years. Pentax, for example, now offers a silent shutter on its KP DSLR, although this is only usable in live view, where the mirror is already up and where an electronic shutter can be employed. More recently, Nikon, who had long offered a 'Quiet' release options on its DSLRs, introduced a genuinely silent shooting setting when using live view. Impressively, this captures bursts of images at 6fps, or up to 30fps at a reduced resolution. It seems entirely likely this feature will find its way to further Nikon models over the next few years, although this is not a widespread feature on DSLRs as it now is on mirrorless models.
It seems very likely that for the time being, DSLRs and mirrorless cameras will continue to co-exist. As we've seen, both systems have their pros and cons, and many users heavily invested in any one particular format be discouraged to trade everything in and start again. Of course, there's plenty of overlap here too, with DSLR users sometimes having a mirrorless option a second camera, and users with plenty of DSLR lenses continuing to use them on mirrorless bodes though adapters, but most people will prefer to just invest everything in one system.
As this year's releases should make clear, both formats will continue to develop to justify their existence. While the breadth of very capable and highly specified mirrorless options arguably make these the more tempting choice for those not tied to any one system, it's difficult to deny how impressive some of the last few years' worth of DSLRs have been, from the feature-packed, affordable Pentax K-1 and Canon's do-anything EOS 5D Mark IV, to Nikon's mighty D850 and DX-format D7500.
While Canon and Nikon's dominance in the DSLR market makes it highly unlikely that we will see any new competitors here, it's possible we will see something new in the mirrorless sector. And this is precisely what stands to make the biggest difference to the landscape over the next few years: whatever the big two DSLR players do next.
While it's extremely unlikely either company will change anything for its DSLRs systems, rumours of both companies developing full-frame mirrorless cameras refuse to go away. This may well have started as nothing more than wishful thinking from photographers, but recent comments by Nikon, together with a general lack of activity in its 1 system line of mirrorless cameras, suggest that whatever it does next will be significantly different from what it has released before.
Quite what that will be is still a mystery, and we're likely to see lots of speculation in the meantime. One thing is certain though: whether we opt for a DSLR or a mirrorless cameras, we've never had it so good.