Maybe mad is a strong word, but, it isn't just $100m, That's one investment by one company. It's billions of dollars across the world to gain arbitrary milliseconds.
Restructuring financial markets, to use periodic auctions for example or by adding speed bumps rather than continuous trading would probably do away with an entire wasteful industry and benefit the actually relevant parties in the financial system, people who have money, and people who need money, at the cost of the unnecessary middlemen.
I get it, just seems... unlikely. Who cares?