A lot of that has to do with how rapidly the world is changing these days. I don't think it is fear of missing out as much as it is fear of being obsoleted.
It was a lot easier to say, 'maybe I'll sit this one one out' when you were not thinking your entire vocational industry might vanish over night, imagine being in the video rental business or a music store in 2010. How many shop owners would really have imagined after 60 years of people successively collecting records, tapes, vhs, dvd, blueray, media that it would go from mass market, to basically boutique segment for diehards overnight.
Same thing with our politics and social mores. We went for 60 years in most of the Western world for fearing socialism to having a huge portion of the populations and majorly political parties embracing it. We went from that will get you beaten to death or involuntarily committed, to maybe its alright if you just don't talk about it and mind your business, to pride month in the span of single generation. None of this is limited to white collar chattering classes either, imagine if as a farmer you spent the last 25 years in suspended animation and woke up today? -The pageantry of the county fair is about they only thing you'd be familiar with, equipment, market place, scale of operation, all radically altered.
The face of the world has been changing a great deal more rapidly than at any previous era in history since the industrial revolution, that pace increased sharply in the post-war era, and has gone asymptotic in the 21st century. People are trying to catch the next big fad - not because FOMO but because they are not sure they will having anything to fall back on if they do miss the wave.