I agree with most of what you say except that this was an uncharacteristic defensive display by us.
As stated by others, we have shipped loads of goals against SPL opposition in the recent past and against the likes of Dundermline and Morton in the Championship. In quite a few games in which we have either drawn or won, this was often partly down to poor finishing from the opposition - we are cut wide open far too easily despite our current league position. I accept that there are signs that things are improving and I hope that this is the case.
Sadly, we often get at each others' throats on this forum, when someone states the obvious about our deficiencies, but I am sure Jack will address these as soon as practicable if he has not already done so.
The reason we are currently sitting top of the league is because of a combination of good organisation, team spirit and individual performances, but we will have to improve significantly to survive in the SPL if we go up at the end of this season.