I personally disagree, myself. But, i do recognize that theory does have logic and is an interesting take on it. Albeit probably completely impossible, other than through a reeeeally slooow and incremental long term cultural shift.
On your suggestion of reverese devolution that is, not on Ruth Davidson as PM, who is grossly overrated imho (but still the best the scottish conservatives have had). She had a flash in the pan moment of passionate case for remaining in the EU (which i myself really liked) somewhat beyond her party line. Which was hugely amplified by the media. And timed really well with labour and libdem leaders being both useless and unlikeable, which at BBC a time of backlash at the snp and post 'neverendum' fatigue made her by default the only semi credible opposition. She has done really well to create an image of herself, but anyone that has seen her in the Scottish Parliament, can think that she is a one string banjo, and an out of tune one at that. She has done really well though, in the way she has removed and distanced herself from the current shitshow, and managed to make it look like an act of integrity and dignity for the Scottish audience, while not pissing on otlr pissing off her Party heirarchy. She can then bide her time and come in as a credible player when it suits her and the circumstances are right, and i'm sure at that point she will be.