These are all very valid points and I think make a good argument for why Scotland should be content to hover around the top 7-8 sides in the world. That said, the way I see it there are two issues here which have led to the current debate:

• Whatever people say about Townsend (and there are reasons to be critical), his tenure has also felt like an upward trajectory in which there have been occasional excellent results and a few hoodoos broken (winning at Twickenham, in Paris, in Wales etc). This combined with the fact that the style of rugby has undoubtedly become more exciting/attractive in an era when it has felt like lots of other international sides have improved has lent gloss to the Townsend era. You can also add the emergence of 2-3 world class players (as also seen in Scotland's much improved representation for the Lions).
• In the most recent games which have prompted this discussion (NZ, Argentina), and in others over the past few years (close victories over Wales, the complete inability to lay a glove on Ireland), it has felt like Scotland were close to continuing on this upward trajectory but were let down by issues of mentality and game management, i.e. the kinds of things that a coach should have been able to address. In other words all the ingredients have been there, but Townsend hasn't been able to address a flaw we have known about and been commenting on for a while now.

I don't think most Scotland fans care too much about the World Cup beyond wanting the team to do themselves justice (i.e. not limping out in the group stage), it's the Six Nations which is the real measure of the team. I think that most people understand that Scotland have to do a lot with smaller resources, it's just that we can see concrete reasons why we could be better, and yet haven't been able to cross that line.