Yes, that fashion's seriously on the decline.

You never did need a big/120hp bike, indeed you're better off without one. The modern GS BMWs and the like weren't built to go adventuring on, they are designed to go on your usual 70 mile sunny-Sunday ride out, visiting your regular biker-cafe stops - using the inbuilt GPS of course - while wearing >£3000 worth of clothing to make it look as if you'll be heading off along the silk road early next week.

As to seeing a lot more small bikes coming onto the market, that's about changing customer demographics:
In the nineties/noughties the fashion was to whizz around on your race-replica sports bike. Ten years on, those same riders' backs & knees could no longer cope with the riding positions, nor could they fit in the tight leathers, so the industry sold them 'Adventure Bikes' instead. Much easier to pootle around on and the riding gear was far more spacious. Now of course, yet another ten years on, riders are finding those a bit too heavy to get on/off the stand, or manoeuvre around the car park; so the industry is selling them Enfield Himalayans and the like... much easier to handle, but you can still pretend (to yourself at least) that you'll be doing something more exotic than turning up here for another bacon butty and a cup of tea next weekend.

'Adventure Bikes' and all the associated gear that goes with them have never been anything more than a marketing tag; no one motorbike is any more adventurous than any other... It's their riders (and only a very tiny proportion of those) who are the adventurers

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BobnLes