Regarding Point 4: One recurring point in a lot those post-mortem articles is how hard it is to sell software, but how (relatively) easy it is to sell service (incl. consulting). Why is that?
This is usually false. Customers are not familiar with the software, they may have a tech knowledge gap, its usage may entail organizational change. There are many possible reasons for adoption to be a very relevant factor.
Consulting means you are responsible for the whole process, not just providing software.
People don't buy new network infrastructure for it's own sake, they purchase a solution to eliminate bandwidth issues and increase productivity of the employee base.
This is why a lot of tech companies have professional services departments internally as well as partner out with established players who already have clients, because customers want solutions, not technical details.
People subconsciously feel that paying for someone's time is "fairer" than paying for something that's already built.
It may also be why aftersales and support contracts are so lucrative (in lots of industries).
There was that article on Joel on Software a long time ago about how they chose to price their software at $999 because $1000 was the typical amount that required approval. Similar to that.