Economy is a fine tuned system with lots of interdependent parts, any sadden change can have destructive effects. If many people will loose jobs at least two things will happen: 1. they'll stop buying products and services (may be except food), companies who provide these products and services will layoff employees even if their employees are not yet replaced by AI 2. people who lost jobs will default on mortgages causing financial crisis worse than 2008 one. UBI and wealth taxes will mitigate effects to some extent but it looks like political elites across the spectrum are controlled by wealthy people - even left of the center politicians prefer to tax middle class steering away from taxing the rich (both people and companies) more.