I don't think this is true, I think you are just overestimating the abilities of even the most advanced chatbot technologies. You get presented with a traditional conversation interface and you are expecting the level of communication you would get with an actual person, but all current consumer chatbots (including Siri/Google Assistant/etc.) fall horribly short in offering a seamless, fluid conversation. The result is a really unpleasant experience made worse by high expectations.

We are just way, way off technologically.