I think you should let people dream. Very few people start billion dollar start-ups - but there are skills and insight being provided here that is highly transferable.
Start-ups are frequently on the cutting edge of business practices - the ideas that are generated here often have impact for people working in big business as well.
Whilst I somehwhat agree with your sentiment, I actually think the content of the course (thus far) is acutally pretty consistent with what you've said above.
The main takeaway from the last lecture was identify a good problem and a good idea that resonates with you personally - or as you phrased it "solve real problems".
The key difference between a start-up and a normal small business is that a start-up's main aim is to grow very quickly to benefit from the economies of the business model. Unfortunately in that environment raising venture capital and working 80 hour weeks is a bit of a fact of life - I hope some people take away from this course that there are other options to this. Specifically a slower self-financing growth phase, bank loans or family/friends etc.
For those interested in different approaches to weight loss, I found this article really helpful while trying to shed a few pounds myself:
http://liamrosen.com/fitness.html
Couldn't help but notice that book has a terrible review from the author John Seddon - although he has always been a vocal critic of management thinking such as lean.