Startups are really just businesses. So, when people say "I'm going to do a startup", why don't they just say "I'm going to start a business". Well, partly because if you said "I'm going to start a startup" it would sound redundant.
But why don't we say "business" instead of "startup"? The just-so story I am drawn to is that startups must be disruptive. A business can be opening a chain of car washes, or a McDonald's franchise. Nobody is going to use the word 'startup' there. However, what if I started a business, and my goal was to develop a paint that never required washing. That would almost certainly be considered a 'startup'.
Now, when you disrupt, you are disrupting commerce that is happening. It's real money changing hands, people's jobs and so on. For the 'no wash paint' startup, success means putting all the car washes out of business, eventually anyway.
Finally, should we care? No. Nearly every business would fire all of it's employees if it could. The carwash you are putting under? If it could do the same quality of washing with half as many employees, it would fire half of them. If it could do the same job with no employees, it would fire all of them. The point is that there is no moral issue here, merely an issue of who is going to collect the money. And of course the money not going to carwashes will go to something else blah blah blah saddle makers blah blah blah Model T.
Now, there is a Player Piano scenario to worry about. What happens when, inevitably, we automate all the mindless tasks we currently pay people to do? Sure, lawns will look great, cars will be clean, shelves will be stocked, houses will be immaculate, and you'll never see peeling paint again, and ipods will be fully assembled by robots. What are all the mindless people going to do? I don't honestly know. We need to figure this out.