Companies in the sector are on pace to raise at least $500 million in 2020 Alex Wilhelm 9 hours Startup buzz comes in waves, with a particular thesis or focus coming into vogue at certain times. Remember the short-lived boom in chat bots? That was good fun. And there was the ICO craze, which lead every startup you’ve heard to consider the financing option for at least a weekend. We’ve also endured the early-AI bubble, the blockchain rush and a cannabis-driven wave as well. Even sub-theses can see spikes, such as…