There are fewer entities that can place bets like that, which means that it is unexplored and likely has more opportunities. Seed funds with $20mm are a dime a dozen.
With this being said the failures are much more catastrophic when such investments are done blindly, without fundamental market / technology forces (e.g take a look at Theranos or Better Place). I believe this is what you are alluding to.
Good investments in this $100mm + category are precisely justified in terms of demand and precisely justified in proof of technology execution -- they are largely for scaling technology to fit a known demand.
A fundamental paradigm shift happened in the past decade which Peter Thiel describes as "moving from the world of bits to the world of atoms" ... this necessitates larger capex to win. With software the scaling costs are constant, with atoms -- they become linear.
This paradigm shift was driven by mobile technology and AI ... so the world is completely different from the days when spreading 10 $1mm bets was a solid strategy. One of the fundamental problems with applying past intelligence is that it was built on top of a different world.