There is a lot of hype about chat bots but let's not confuse that for usage. Tell me what chat bot you use on a regular basis? To me, chat bots seem like a step backward, at least for the use cases I've seen them applied for.
a) The anticipation that AI will be good enough to understand an instruction set through sentences. In some cases it already is.
b) Text isn't so much the interface but audio-voice interfaces are. The stuff from A) combined with voice recognition.
It is somewhat weird because Siri has been around for a while, Google voice recognition/search has been around for a while and been really good. Maybe the big aha moment was Amazon letting users actually input commands like ordering a product rather than getting dumped on search results for the web page to do it.
If the whole chat-voice-smart assistant thing is a winner takes all market, that winner probably replaces Google in mass market use cases for search. That is a really big deal and companies are salivating over the possibility.
Perhaps another factor is because other companies don't really have a knowledge graph like Google's, they are letting third party developers plug in.
So, the big tech companies have their products commercially available already and are being used by lots of people, the small tech companies have stuff they have been working on and are joining the hype cycle in hopes of being acquired.
So in summary the larger story is "chat bot" really = AI voice assistant which is plausibly the next Google eclipsing platform, and about as massive of a deal for the tech industry as the smart phone and self driving car.