There are fundamental core reasons why stacked is better for global shutter - it's not just a "nice to have", the fact is that unless you either go BSI, or you go stacked because you only have so much silicone space. On a normal sensor for efficiency, you need all that space taken up for photodiode wells. Anything that gets in the way of that will cost you stills dynamic range performance. That's just well, physics. Sony's done several different novel solutions (and even Canon has come up with a few) but all of them are based upon stacked designs. Usually three-layer designs so you can incorporate memory. Canon's done more R&D on global shutter stacked designs than global shutter non stacked designs. To get around using stacked you have to use novel solutions such as time slicing. but it's imperfect for both video and stills. you can get around it in video by making the slices smaller and smaller, but that's still not a good solution for stills.
To get too stacked sensors, Canon first has to develop a BSI sensor. They haven't even gotten that far yet. So no, when looking a "past development trends" there's really nothing out that that suggests Canon is about to shove a global shutter sensor into what is a stills camera first and foremost.
I've seen articles that mention the biggest deterrent to this tech (in 2017) was the inherent loss of DR, but nothing about Son'ys stacked sensor design. I imagine the stack sensor may be inherently better, but I haven't read anything that suggested it or similar tech was needed. I don't understand the tech well enough to know whether the stacked sensor poses any hindrances based on the architecture their global sensor, but I don't think that's a stretch either.
From the article, GLOBAL SHUTTER IS COMING TO CANON DSLRS ...EVENTUALLY, Written by George Shaw
From Canon, "...However, its dynamic range is narrow. To solve this problem, Canon made two major improvements. " The improvements Shaw refers to, "...Canon has improved this issue by doubling the saturated electrical charge coming off the photodiodes and then reading the data twice during processing. The result is that the sensor can read up to 16,200 electrons at 60 frames per second, while the original sensor data is 8100 at 120fps ".
Canon has also added a so-called “light guide structure,” which reflects more light onto the photodiodes in order to read the maximum amount of image data off the sensor. In order to accomplish this feat and not fall behind like their rolling shutter cousins, the new global sensor uses Canon's A-D (analog-digital) converter called "SSDG-ADC" to keep up. Both these improvements provide greater dynamic range, with less noise and under .45w of power consumption, easily better than a CMOS sensor reading the same image using rolling shutter.
Again, this is not a theoretical sensor, they have current distributors in place for the industrial CMOS sales now. This is tech that is well down the road with a little maturation. Unfortunately, I can't find the white paper Canon published on it a few years back, but I don't think that is necessary to prove the point. Canon has been busy.