I think it is more accessible now due to better lighter camping gear. More viable luggage options. Advances in rider clothing.
Harley Davidson is on the decline. Met a rider a few years back who was Harley only for decades, then friend took him out on a loaned BMW GS the very next day he put his harley up for sale and bought a used GS with cases. Fuel range, ability to go on gravel roads and explore, and upright seating position made riding more comfortable.
Also "some" of the bikes are more ready off the shelf then before. When I got started I put many hours and lots of upgrades into my first dual sport. Today it would not be as expensive and would not require as much mechanical knowledge.
Youtube videos are also influencing this. c90adventures, (once you get past a few of his phallic jokes) shows you don't need a lot of money or a expensive bike to do world travel.