If there is one clear, unbroken trend in the history of "photon-capturing imaging" then it is "ever higher image quality with ever smaller, lighter, more portable, less obtrusive, less complicated gear".
This has been going on all the time since its very invention. And it is still ongoing. Nothing will stop or reverse it. Every step there were hold-outs and earlier generation/larger gear remained in use by a few and/or for small, specialized niches and imaging tasks.
In a few years time we will look back at today's "pro" DSLRs the same way we look at those brick-sized "mobile" phones from only 15-20 years ago. "Did we really use these cludgy devices?" :-)
Recently we passed one major "size category" transition point - the move from dedicated "compact" cameras to multi-tasking mobile devices for "consumer grade" image quality and "consumer image-capturing tasks" ... although both "artists" and "working pro's" have demonstrated that much more can also be achieved using mobile imaging devices. :-)
Next transition point immediately ahead is the the move from the previous-generation concept of mechanical-analogue mirrorslapping SLRs to fully digital mirrorless cameras that will soon deliver superior image capture and image quality, also at the professional" level. Plus native, unobstructed "convergence" of stils and moving images.
It is still a relatively "MINOR" point in development ... while camera bodies will shrink considerably in size, only lenses in the (overall) most frequently used diagonal angle of view range ... from about 84° [24mm focal length on "FF" 24x36 image area] to about 23° [approx. 90mm FL] can be made (somewhat) smaller for mirrorless cameras with shorter flange distance. High image quality, reasonably fast zoom lenses and "longer" tele lenses [with less than about 23° diag. angle of view] will remain as large as they currently are. On the other hand, only a minority of all photographic tasks absolutely dmeand those lenses! ;-) For many situations and photogs, they are infrequently used but still "nice to have" tools for a few specific situations and/or creative effects.
The next MAJOR revolution in size of imaging gear will occur, if/once glass optics are replaced by new technologies yielding even better image quality with smaller gear. Whatever it may be [e.g. improved "liquid-filled variable lenses", lightfield or holographic concepts, ... ] and whenever it may occur. That will yield "implantable-size imaging gear". No matter whether we'd ever want this or not.