We actually know that automation can end jobs. It happened in American agriculture, most intensively in the 1920s-1960s. It doesn't make me optimistic.
A small subset of farmers did very well in the mechanization of American agriculture. They did so because they had more money and connections, and they had the support of the federal government. A much larger number of farmers did not do so well. They were forced to leave the land or live in what amounts to rural ghettos, with many of them or their descendants still doing so. They failed because they did not have access to the resources necessary for large-scale, mechanized agriculture: the capital for machines, the know-how to buy and use them, the support of the federal government and corporate hierarchy. Some of them found new jobs related to the transition, but most of them did not. The benefits did not land equally. Capital-intensive agriculture ran roughshod over rural culture, and we as a people lost a lot in the transition. Thousands upon thousands of marginal people - the poor, racial minorities - never got their share of the prosperity that this was supposed to provide.
So that's my concern. Without some mechanism to ensure that the benefits of economic and mechanical transitions are shared at least somewhat equally, wealth and position will further concentrate among the already wealthy and well-positioned. To make an analogy: Instead of automation ending jobs in just agriculture, it's going to be ending jobs everywhere. Where are those people going to go? Some new fields will doubtlessly pop up, but I don't know that they can be qualitatively or quantitatively enough.
The last time we had a mass movement to emphasize productivity without raising consumption, we got the Great Depression. And just saying, "there are going to be new jobs" doesn't cut it. If your business gets automated so that you have a bunch of minimum wage janitors pushing around machines which replaced skilled mechanics, sure, you've got more jobs. But replacing skilled work with low-skill and low-paying service jobs, then that's not a solution.