Your last point is not untrue it has to be said. Or written, as the case maybe!
One point about Scotland that does seem to be consistently missed by it's detractors in England is that at one time it
was a net-contributer to the UK's finances. During the period of what's termed the "Industrial Expansion", the mid 19th Century until roughly the 1920's to 30's, Scotland consistantly sent
more money south than it received back in spending.
Even taking into account the tax revenue generated by North Sea Oil, during the post WW2 period Scotland has been a net-receiver more often that not. Even with past oil revenues factored in it's barely been break-even at best.
In order for that to change there would have to be either major investment by the UK Government (which prior to devolution only did "just enough" rather than trying to fix things once and for all) or Holyrood is handed the means to improve Scotland's economic outlook for itself. However, as I wrote before, that would upset the UK economy as one region would gain a competitive advantage over the rest.
How to square that circle, I have no idea.
Mike.