Travel agents still exist though; while I couldn't find employment numbers, I wouldn't be surprised if there were more today than 20 years ago (something something's Paradox)

Now, what you're describing is really about the "culture of convenience". People prefer Expedia to human travel agents because it reduces friction (of interacting with people). Same goes for Uber, Waymo and so on. Good piece on it - https://www.cbc.ca/radio/ideas/cult-of-convenience-9.7371392