I wouldn’t say it’s the most significant MTB Revolution ever.
I’d give that to suspension. Suspension, especially platform suspension that has allowed long travel mtb’s to still pedal efficiently. Try to find a new real mountain bike that doesn’t have at least a suspension fork. Suspension has radically changed how we ride and what we ride. Imagine the pros trying to do Redbull Rampage on rigid bikes.
A revolution implies a complete takeover, and a long-lasting one. I don’t think Fatbikes fit that definition, or at least not yet. It’s yet to be seen if they will dominate the market, and I doubt they ever will. Will they be long-lasting, and not just a flash in the pan? Again, yet to be seen.
Do they completely change mountain biking? There are those of us who’ve ridden all winter for years. That’s not new. Do they expand capability? Yes, they can ride in deeper snow than a regular mtb, if you’ve got the legs to push through, and expand the range of rideable conditions.
I’m not sure I’d say that fatbikes are a revolution, but they’re certainly a welcome addition, and if they get more people out more often on more trails in more conditions on 2 wheels… awesome.