True, but they are ideas worth pursuing, no? What you say just means that you'll need to do more research than just this blog post to get yourself started.
Oh yea, lots of room for improvement. In my experience, the concrete suggestions (for niche 1 and 3) aren't necessarily potential niches, but starting points to build more powerful software.
I should note, there is probably a huge opportunity to bring IT services to "mom and pop" style operations. But it needs to be dirt cheap or they won't be able to afford it. Lots of these people are struggling as it is and won't see a direct increase in sales as a result of new software.