filled by those who will toe the party line as the leadership will decide who gets a set from their allocation.

That was true up until and including 1997, perhaps 2001.

It's now the other way around thanks to Blair. Since 2005 certainly Labour's general election success has been thanks to Tory hatred (and the FPTP system)

The ~50 seats you see Scotland handing to Labour in '05 and '10 aren't reflected in the Holyrood elections that took place one year later, they're tactical votes to keep the Tories out.

The referendum simply snapped the straw, people took a deep interest in politics for well over a year and certain realities bubbled to the surface and that's what gave people the confidence/understanding that switching to SNP in general elections might actually work.

1) How far Labour had really drifted from Scots

2) How ineffective the previous tactical voting actually was

3) How Labour were spinning plates trying to please both left leaning Scots and more centrist English

4) How devolution/Holyrood actually works and the extent at which it was deliberately hamstrung by Labour because of their arrogant 'ownership' of Scottish votes.

Your overall point about the Tories is partly true. Scotland I do think typically sees itself as further left so naturally less Tory voting but also I think those that are Tory leaning don't quite align with the actual party. They are more old fashioned small-c conservative liberal than modern Conservative & Unionist Party.

An odd example of this is the continued popularity of Gordon Brown, weirdly. Fife is a good example of that small-c conservative viewpoint, Brown although Labour is seen as a kind of 'stoic, sensible money man' and they like that.

The Scottish Tories in Holyrood I think are also slowly diverging toward that direction. The support is there but the toxic drag of the London-based Conservative Party brand is quite high.