You may be right....1 is much more likely than option 2, however in the high-growth startup space, most people tend to try and go for #2. That's where the returns are. That's where they are usually most misunderstood initially, and that's where they tend to make the biggest impact on the world.
Everything you've described is pretty stupid. I hope nobody is working on the next Google killer or yeah another Facebook alternative. All the big names were purely by accident and luck. Tell this to the graveyard of all the smart ideas that never took off because the market didn't need them.