Over the past few years, the varying advice on decisions as to "Camera X or Y of System C, N or S?" have extended into countless forum threads, particularly as we're photographing in the era of rapid iterations of Mirrorless technology, which has apparently extinguished any relevance of the DSLR.
Rapidly evolving camera hardware is enabling the means to sample the RAW video stream at ever faster frame rates - with the benefits of PreCapture etc... exciting times, accessible if one can afford the latest& greatest

This is all part and parcel of the dynamic MILC market, tempting the consumer with the latest innovative features. We can expect more cameras with a global shutter, Partially-Stacked and fully Stacked sensor, better EVF, more Autofocus features etc.
Evolving faster than turnovers of DSLR tech over the preceding 2 decades, Mirrorless technology is very much a work in progress, particularly with the leading systems also investing their R&D in video (interfacing with still photography). As regards the retail market, well... we can expect mirrorless cameras of the relevant mount systems (aka brands) to continue leap-frogging each other with the latest innovations.
However, it's particularly helpful to the photographer on a budget that MILC Firmware updates are also turning over much faster than in DSLR era. Although update frequency and the new features differs greatly between the systems.
I agree with the wise advice, which is to invest in the Glass and recycle the camera(s); which in turn depends on when an improved camera supersedes the performance and features of one's current model with respect to personal needs. Trying to surf the crest of the tech wave is impossible as it is expensive to keep up with the "latest" camera, including this year's leading mid-tier model.
(Edited)