Naive finance question: why do stocks have a an exchange they are listed on if they can trade on multiple exchanges and dark pools?

part of it is that exchanges (NYSE, NASDAQ, etc.) want the business and everything that comes with/around it (more than just trading), but the other important aspect is that it centralizes (vs. fragmenting) liquidity, enabling higher volumes, better price discovery, and lower volatility

10 years in crypto. co-founder of @syndicate

if a mainstream company (e.g., Apple, Airbnb, Uber, etc.) wanted to make its shares available to as many people as possible, especially retail/consumers, it'd be chaos (e.g., price/market manipulation, arbitrage, etc.) if liquidity was fragmented and small across many venues